West Elm - their Gallery Frames collection is simple and basic. Frames are available in black, white or painted silver finishes in a variety of sizes. Currently, prices range from $16 - 54.
Urban Outfitters - The ultra bargain choice if you are looking for simple black frames in a variety of sizes. They sell a set of ten frames for $28.
American Frame - we've heard good things about this online retailer - a really wide selection of basics, good prices, free mat with each frame.
and of course,
Ikea - a framing staple for many of us, the Ribba frames are somewhat legendary for great prices and good quality.
Got another source that we should add to the list? Let us know in the comments below...
Image: Pottery Barn