This is probably my favourite place to buy prints from. It's basically a website where artists can sell their work and get it printed on pretty much anything you can imagine. I have so many prints from there but some of the ones I've got are pictured above are linked. There is so much work on there it's really worth trawling through looking for the style and look you want. I currently have about $500 worth of prints in my basket at the moment waiting to be ordered! Be warned you will be charged customs on large orders, which is obviously dependant on how much you order. There are tons of online calculator to predict how much tax you might be charged though so it's worth factoring that into your budget.
This is another place for artists to sell their work but this time it's purely stuff thats produced and sent by them. It's worth searching for printables too which (if you have a printer, obvz) you can print out at home to save you even more money. I search for things like "minimalist prints" "typography prints" or "XYZ (for example a film) prints". Stuff like that just pops up. It's worth browsing for sure!
& The Frames...
Pretty much all my frames are from Ikea. I personally like the Ikea Nyttja frames purely because they are lightweight. As they dont actually have glass so they are thin and light. Therefore attaching them to the wall with contact strips (I use these ones) or blutac works well and doesn't leave holes in the wall.