I have a review of GF9's Econo Bases up on my blog. Essentially they're made from fiberboard (aka masonite) cut to just about whatever shape and size you desire for a pretty low price. I use them all the time for minis that have tiny, wobble-prone cast bases and I really like them. Anyone interested in more details including photos should follow the link.
I'm afraid that those outside the USA won't find them of much use, since I can't imagine what overseas shipping would cost, but I know a lot of folks from North America frequent the board so I thought I'd post it anyway.
http://thescreamingalpha.com/2009/01/18/review-econo-bases-by-gale-force-nine/-Curry