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Point-of-sale and business management for tyre and mechanical workshops.

Specific Cost Products

Learn about Specific Cost Products in Marlin GTX trusted automotive software by Megabus.

Updated 30 October 2026

Marlin GTX enables businesses to manage made to order or non-standard products by grouping individually purchased items under a single specific cost groupings.

Specific cost groupings stand in for kinds of products that may be ordered as required, rather than keeping specific models on hand (eg. brakes, engine parts, batteries, etc.).

The broad product grouping is first added as a "specific cost product".

Specific products can then be added to the grouping by adding them to a **Supplier Purchase Order** or during Stocktakes and Journal Entries.

Adding Specific Cost Groupings

Specific cost items can be added by selecting Specific Cost from the Costing method drop down, when adding a product in Product Maintenance.

Screenshot from the Specific Cost Products BT help article

The rest of the product information can be filled in as usual.

Specific products can then be added to the grouping by adding them to a Supplier Purchase Order.

>default cost/prices can be entered? Otherwise, leave blank >>The price fields (except Avg Cost) can be edited whenever as long as it's a locally maintained field. You can change the price on a PO on the spot, but that won't affect the default price you've set up in Product Maint.

Items Tab

Specific products that are currently in stock can be viewed by opening the specific cost grouping in product maintenance and clicking on the Items tab at the top.

Screenshot from the Specific Cost Products BT help article

Once a specific product has been sold, it will be automatically removed from the list.

Purchasing Specific Cost Products

Specific products can be added to specific cost groupings by adding them to a Supplier Purchase Order.

Screenshot from the Specific Cost Products BT help article

To add a specific cost product:

  • Select the product grouping using the Product picker
  • Enter the specific name of the product in the Description field
  • Enter the Quantity being ordered
  • Enter the Cost of the specific product
Tip — Specific Cost product descriptions can also be built automatically, using the Description Builder The order can then be finalised as usual. Once the product has been received and brought into stock using either a delivery docket or supplier invoice, it will appear and be selectable for purchase as part of the specific cost grouping's item set.(Warning) (Warning) You cannot edit a specific cost product once it has been used on an invoice. If you need to change it after it has been used, you will need to either clone the product or add a new one and edit the details for that. :::

Description Builder

If the Description Builder is enabled, you will not be able to enter a Description when purchasing or adding specific cost products.

Instead, you will be prompted to:

  • Select a Brand
  • Select a Size
  • Enter a Pattern (free text, up to 20 characters)
Screenshot from the Specific Cost Products BT help article

The description will be automatically built from these fields using the following format:

  • BrandPrefix + SizeName + Pattern (free text)
  • This will be previewed below and automatically enetered in the Description field, once saved. Note: The description will be trimmed if the total length exceeds 30 characters
Screenshot from the Specific Cost Products BT help article

See the Description Builder help guide for more information.

Note — The dialogue box may vary slightly, depending on whether the item is added via Purchase Entry, Stocktake, Stock Adjustment, or Journal Entry.

Adding Specific Cost Products

Specific cost products can also be added to groupings using Journals and Stocktakes.

Journals

>not sure about the text/image order here. Feel free to swap around as you see fit. Usually I'd introduce each new window with its own line of text "The XXXX pop-up will open."" but there's so many pop-ups here that it gets too wordy. >> I think the way you built the information below is very clear and it looks good.

To add a specific cost product:

  • Click on the drop-down arrow to the right of the **Add** button
  • Select Stock
Screenshot from the Specific Cost Products BT help article

In the Product Details pop-up that opens:

  • Use the Product picker to select the specific cost product
Screenshot from the Specific Cost Products help article

In the Outstanding Specific Purchase pop-up that opens:

  • Click on the New Item button at the bottom-right
Screenshot from the Specific Cost Products help article

In the Product Details pop-up that opens:

  • Enter the relevant information
  • Include a specific Description
  • Click Ok
Screenshot from the Specific Cost Products help article

The product will be added to the Line Details list:

  • Additional information can be entered in the Narration column, if required.
Screenshot from the Specific Cost Products help article

The product will be aded to your inventory when the journal is Finalised.

Stocktakes

Specific cost products can also be added during stocktakes, if required.

To add a specific cost product:

  • Click on the **Add Stocktake Item** button at the top
  • Select Add New Specific Cost Item to Stocktake List
Screenshot from the Specific Cost Products help article

In the Add New Specific Cost Item to Stocktake List pop-up that opens:

  • Enter the relevant information
* Include a specific Description
  • Click Proceed

>allow description override - checkbox

>Can't enter a description?

Can't edit anywhere else >> Not sure what you're referring to here ^
Screenshot from the Specific Cost Products help article

The product will be added to the Stocktake Entry list:

  • Enter the Count
Screenshot from the Specific Cost Products help article

The product will be added to your inventory when the stocktake is Finalised.

>It is very annoying that the processes are completely different across the different modules and that even the buttons are called different things. Also that it is inconsistently referred to as Stock/Item/Product. Makes my job hard and our software unintuitive.

Merging Specific Cost Products

Specific cost products can be merged together, using either the Specific Cost Maintenance module or during customer invoices or work orders.

Note — In order to merge specific cost products, Allow Posting must be enabled for the Stock Costing Variance account (20850).
Screenshot from the Specific Cost Products help article

:::

Warning — Once a specific cost products have been split out, they cannot be re-integrated into the original grouping.

Specific Cost Maintenance

Specific Cost Maintenance can be accessed by selecting Main > Products > Specific Cost Maintenance.

Screenshot from the Specific Cost Products help article

The Specific Cost Item Maintenance module will open, showing a list of specific cost groupings.

Screenshot from the Specific Cost Products help article

To merge specific cost products:

  • Select a Salesperson using the picker at the top
  • Double-click on the relevant grouping
Screenshot from the Specific Cost Products help article

In the View Specific Cost Item window that opens:

  • Tick the Merge checkbox on the right for each product you want to merge
  • Click on the **Merge** icon at the top (or press ctrl+m on the keyboard)
Screenshot from the Specific Cost Products help article

In the Merge Specific Cost Item window that opens:

  • Enter the relevant information
  • Include a specific Description
  • Click Merge

Customer Orders / Invoices

Specific cost products can also be merged when adding them to customer orders or invoices.

To merge specific cost products:

  • Select a Salesperson on the invoice / order
  • Add a specific cost grouping to the line Details list
Screenshot from the Specific Cost Products help article

In the Outstanding Specific Purchases pop-up that opens:

  • Tick the checkboxes to the left of the products you want to merge
  • Tick the Merge Specific Cost Items checkbox at the bottom-left of the pop-up window
  • Click on the Merge button to the right

>checkboxes untick but are still selected when you tick merge checkbox, need to tell Duncan

why is this checkbox even here? - used to enable checkboxes, but now they are just there already - should remove
Screenshot from the Specific Cost Products help article

In the Merge Specific Cost Item window that opens:

  • Enter the relevant information
  • Include a specific Description
  • Click Merge

Specific Cost Enquiry

A full list of currently stocked specific cost items can be viewed using the Specific Cost Enquiry module, which can be accessed by selecting Main > Products > Specific Cost Enquiry.

Screenshot from the Specific Cost Products help article

Specific item details can be viewed by selecting the product in the list.

Screenshot from the Specific Cost Products help article

Unit Cost, Total Cost, Gross Profit and Gross Profit Margin details can also be shown by clciking on the Click the Stopwatch icon at the top.

  • These columns will disappear after about 10 seconds, or you can toggle them instantly with the Stopwatch icon.

>why use this and not spec cost maintenance?