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Stock & Inventory

How to Build a Simple Reseller SKU System

A stock code is just your own stock code. Use it to connect an online listing to the box, rail or shelf where the item lives.

Updated September 2026UK-focusedFree guide
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In simple terms

stock code is just a stock code you make up yourself โ€” for example TUB3-014 โ€” so you can find the item after it sells.

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Quick answer

A stock code only needs to be unique, readable and connected to a physical storage location. Treat every physical item as one unit with one identity. The record should tell you what it cost, where it is and whether it is live, sold, returned or written off.

What matters most

The easiest way to think about how to build a simple reseller sku system is to keep it simple. Use the facts you know, keep the important details together and learn from what actually sells.

  • Keep the code short
  • Avoid encoding too much information
  • Print or write the stock code on the storage bag
  • Never reuse a stock code for a different physical item

A practical workflow

  1. Start with the item or decision. Record the facts you know before changing price, listing details or stock status.
  2. Check the money. Use purchase cost, expected or actual sale price, fees, postage and packaging so the outcome is based on profit after costs.
  3. Make one clear change. Change the factor most likely to matter instead of editing everything at once.
  4. Track the result. Save what happened so future sourcing, pricing and listing choices get better.
  5. Review in batches. Weekly or monthly reviews are more useful than reacting emotionally to one item.
MyCost tip: attach the cost, channel, listing status and eventual sale to the same stock record. That makes it much easier to compare what you expected with what actually happened.

Numbers worth tracking

You do not need a giant spreadsheet. These few numbers are usually enough to tell whether things are working:

Stock cost valueMoney tied up
Stock ageDays since purchase/listing
Sell-throughHow much stock moves

Common mistakes

  • Reusing stock codes
  • Keeping duplicate master records across channels
  • Leaving lost/damaged stock active
  • Measuring stock by optimistic asking price only

What to do next

Try this on a small group of real items first. If it helps, make it part of your normal routine. There is no need to change everything at once.

Related guides

Quick questions

Do I need special software for this?

No. You can start with a clean spreadsheet or notes. Software becomes useful when you have enough stock that manual updates are slowing you down or causing mistakes.

How often should I review it?

For active sellers, a quick weekly check plus a fuller monthly review is usually enough to spot problems before they become expensive.

Should I optimise for the highest possible sale price?

Not always. Money coming in and going out, days-to-sell, risk and the amount of work involved can make a slightly lower but faster, cleaner sale more profitable overall.

Track this automatically in MyCost

Stock, costs, sales channels and real profit in one place.

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