FCB electronics is a good USA ebay seller. They have inexpensive items with fast and FREE shipping. I bought the smaller version of the matrix from them so I can fit more on a breadboard. I don't have Osgeld's high precision ninja soldering skills. 
Scroll down a little bit on this page:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=150386988451