For those of us that can't afford original works of art, prints are a great alternative. I have made a list of almost 30 places to purchase prints.

http://plastolux.com/my-list-of-modern-prints.html

I use American Frame for all my framing needs. Right now they're having a 20% off sale on all their metal frames. Also, with each order you're entitled to 5 free frame chop samples.

http://www.americanframe.com/

i get my art framed at Tugboat Print Shop but they aren't in DC

http://www.tugboatprintshop.com/

Anyone can afford original art on Etsy. And don't forget photography!

www.ugallery.com
www.artfulhome.com

The first site is an online gallery for art students and recent grads, and is very affordable for the quality of work. The second is an online marketplace for more established artists, including those working in craft media and home decor. The prices are consistent with what one would pay retail.

Curator's Office for art (source of my beloved "Hello Kitty masterpiece" series of paintings by artist Leslie Holt.

On line there are some great resources as well-although she recommends FAAN I've never had much luck there and frankly some work is still sitting there after a year...

Anyways there two are knockouts and they support emerging artists:

www.tinyshowcase.com
www.20x2oo.com
http://athousandsmallpaintings.blogspot.com/ (Duane Keiser's smaller/tiny works)
http://www.etsy.com/shop.php?user_id=5060033 (Amamda Kavanagh's wonderful prints and smaller paintings)

etsy stores such as Amanda's are a source of some amazing art, most very nicely priced-and something for almost any taste.

The Torpedo Factory Bin gallery has some very reasonably priced works.

I wrote this blog post a while ago-it also has some good sources for art that won't kill you bank balance

http://mongoose1.wordpress.com/2008/03/04/a-way-to-collect-art-inexpensively/

Artist Sarah Grote (clifftopstudio.com) is in the DC area and does great commission work in oils or watercolor.
Katy
http://fengshuibyfishgirl.com

Framer's Workroom on Wisconsin Avenue in Tenleytown is one of the greatest DC treasures. It's just down the block from the Tenleytown-AU Metro too! It's really a nice place to go on a Saturday due to the "Do-It-Yourself" option, and the friendly experienced staff can frame anything (and I do mean everything) under the sun. They offer archival framing, if your work is of the more valuable variety, and sell matting, mounting, canvas stretching, etc. The address is 4431 Wisconsin Ave NW, and trust me, it's one of the best and friendliest places to go in DC.

Check out an artist living in the DC Metro area, she has really cool pop art prints and originals. I own a few of her pieces and just bought a print on sale.

http://www.tanekeyaword.com/Purchase_Gallery.htm

I came across this artist's online gallery and love the concept and look of his work. The prices were very affordable as well...

http://mikearick.com