i've personally had luck with rugs from chairish, kaya kilims, and one not listed below, pillows store on eBay. here is the list from studio mcgee but go to their blog to see the full post with links!
a few tips -
1. search until you feel like you've exhausted the internet. there are treasures hidden out there! i spent one night on vacation searching for hours but in the end i did find a really pretty rug for not a lot of moolah.
2. negotiate price! especially on eBay but etsy too and particularly if it's a foreign seller. i've had luck asking for 10-15% off the purchase price.
3. ask for additional pictures if you don't feel like you've seen every angle in the pictures on the site. i bought one rug that in person looked pretty different from the pics online and i think it had to do with the lighting. i wish i had bugged them for more pics.
4. remember these rugs are not supposed to be perfect. some wearing or fringe missing is part of the story so embrace it!
5. if you like it, jump on it. the good ones go fast and if you hesitate chances are it won't be there after you've thought about it.
there are some great finds out there as we speak! here are some pretties for you...