I haven't sold on ebay in years but the first thing I'd do if I started again was look at the tables of fees and work out beforehand how much I'd be up for. Then factor that into my asking price.

I used to sell way back in the early-mid 2000s and the fees then soon added up every month. I don't know why you think this was ever a 'free' site for sellers. I can assure you it definitely wasn't.

Ebay isn't greedy but they are in business. If you want to use eg gumtree, that isn't free either if you want to promote your items and if you don't, they soon travel to about eg page 10 and get very few looks.

Marketplace is free but good luck getting your asking price.