I did well at a market, took a bit of time putting nice things into bags with stickers to show the price and made a chart thing and then had a hanging rail for some better things. With the cost of the market split between us, we both made a good amount - I made around $150 and she made $200 ish because she had more nicer stuff! I thought it was well worth it for a few hours work.

The only thing I have made super good money on ebay was an old gym set we didn't want to take to the tip - put it on for 99c just hoping someone would take it off our hands and ended up making around $150