Needles & Grooves

Etsy is probably your best bet. I've bought some posters for friends/family/myself along with nice frames on there.

I make all of my wall art. But if I do need something from another artist, I really like 20x200. They have runs of limited prints by both well-known and emerging artists, very nice quality. 20x200 | Art for Everyone Starting at $35

You can get cheap prints. The frames are what kill you.

@TheThinWhiteDuke Thats why I'm starting took at canvas prints. Don't really care about quality, don't need it to last a long time. Just something visually interesting.