Someone messaged me about buying an item I had in my stash, but I didn't set a price on it.

Today someone messaged me about buying an item in my stash. However, I did not set a price for it. The tab is public, but not every item is for sale. How did that person find the item? They were buying it for 10c, but the cheapest on trade is 2c. I tried searching for the item myself, but it doesn't show up. I even set the seller's account to mine and it still doesn't show up. Does anyone know how this happened? This is the first time something like this happened to me and it's a little unsettling (heh). Thank you!

You don't need to price an item for it to show on the trade site.

As long as it is in a public stash and you haven't marked it with a ~no index flag, it's going to show up. That's the whole idea behind dump sale tabs, which many people use so that they don't have to price check every item - the market does it for them.

If it's on public stash tab it would be visible. If you want to put an item on that public tab but have it not viewable on trade, right click the item as you would normally to price it, and set the item to do not index.

I think at some point they made inventory viewable of non-trade stash tabs as well. So people could potential see items you have on your other inventory tabs in the character profile. I think you have that set to private currently, I can see your character profile is visible, but stash showcase is not.

Sometimes will happen, it's intended to work like that. Not sure why you can't see it on trade your self exactly, probably you are not searching with the correct parameters. Try listing the buyout type as "no listed price". Doesn't look like you have any items listed without a price in Settlers league currently.