I don't know where abouts you are located, but have you looked on craigslist?
There are some wicked deals to be had.
Here are a few from my area. The key is checking often, because anything awesome & cheap won't last long.
I just picked up an almost brand new Sims board with Sims bindings for free off craigslist, later that afternoon I got a pair of Burton Mission bindings for $10
***NEW*** Women's K2 Snowboard
Rossignol Circus Snowboard 2011 with k2 bindings
Forum snowboard + boots ( women's)
K2 Skyla Snowboard 149cm with burton bindings
K2 Vava Voom
2007 rarely used K2 snowboard for sale