Scan marketplace listings overnight and flag underpriced items
Idea + starter prompt, not run by us yet
For: Resellers and collectors who hunt for underpriced stock on online marketplaces
Alessio Finelli gave a Codex agent a short skill file listing target cards, grading companies and a limit of 5 listings per batch. It goes through eBay listings by itself, reads grading certificate numbers, compares known prices and flags cards that look cheap. He reviews the flags for his shop.
Steps
- Write a short rules file: what to look for, price limits and batch size.
- Keep batches small. The author used 5 listings to avoid bans.
- Paste the starter prompt and have it flag only, never buy.
- Check each flagged listing yourself before buying.
Starter prompt
Read my rules in [rules file]: target items, maximum price and batch size of [5]. Check listings on [marketplace] for [search terms], one batch at a time. For each listing, record the link, price, any certificate or serial number and the known market price from [price source]. Flag listings priced at least [percent] below market. Do not bid, buy, message sellers or log into my account. Give me the flagged list with links.
Original post: X · @Scantor22 · found via agentusecases.ai. Written up in our own words. We haven't run it, so test it on made-up data first.