One number beats every opinion

Ask ten resellers what sells and you will get ten confident opinions. In one American clothing dataset, the brand every guru recommended sat mid table, while a workwear label most people walk straight past was selling through at nearly three times the rate. Opinions run on memory. Markets run on numbers, and this course teaches you to read them, so you never have to bid on a hunch again.

The master number is sell-through rate: how many of an item actually sold, compared with how many are listed, over a window such as ninety days. If a hundred are listed and twenty five sold, that is twenty five percent, one in four found a buyer. And when more have sold than are currently listed, demand is outrunning supply, and that item leaves the shelf almost as fast as it arrives.

You can read this on eBay yourself. Search the item, count the sold listings from the last ninety days, then compare that with how many are live right now. Lots sold and few live is a fast market. Few sold and many live is a queue, and your item would be joining the back of it.

Keep the window honest. One sale last Christmas is not demand today, and a viral fortnight can flatter a dead item. Ninety days is a fair default, long enough to smooth out luck, short enough to stay current. And always compare like with like: the same model in the same condition, not just the same brand.

RedGem reads these counters for you. When a lot is valued, we check eBay's own sold numbers for that exact product, and the feed shows it as a chip on the card. One real example from our own feed: a Shark cordless vacuum carrying more than four hundred and forty recorded sales. That chip is sell-through talking.

Open the deals feed and find three lots with a sold counter on the card. Before you look at anything else, say which of the three moves fastest. You have just ranked a market in seconds, using the number most bidders never check.