I have made many wallpapers in the past... many inspired by games, and Im aware you can sell them for credits, but where do I sell them? And how much should I sell them for?

Heres an example wallpaper :
(Minimized)

In the Art/Textures section, there. You make a shop if you want to as well.

Hmm, i don't think ive ever seen anyone sell wallpapers before. But I'd suggest selling them In the Art/Textures Section of the Market (Right Here)

As for pricing, you can charge whatever you want, anywhere from 50tc to 10,000tc or even 1million tc. It's your art, sell it for what you think its worth, or even have an auction.

Just make sure everything you sell is yours, and go over the rules in the Art/Textures section of the Market to be sure your not breaking any.

But good luck with this.

Ok, thanks for the advice, but I really dont know what to charge for them, thats why I posted an example. I mean, what would you pay for it? (Actual sizes are 1680x1050)

I'd say it depends on the quality..
For example, the one you posted on your first post was very simple, i actually liked it and make one almost exactly like it in about 10 mins..

Because it didn't take very long, I'd charge like 500tc or 1,000tc depending on if you want to make tc or you do it because you like it. But if something is very detailed, and you put alot of hard work into it, you can sell it for like 7k tc or something. This is what I would do/ how I would price my stuff.