Thought I'd share a good deal on Ubiquiti SR2 cards.
http://cgi.ebay.com.au/Ubiquiti-SR2-400mW-2-4GHz-WiFi-Mini-PCI_W0QQitemZ230374835524QQcmdZViewItemQQptZAU_Networking?hash=item35a3690544&_trksid=p3286.c0.m14
(no affil.)
I picked one up for $60, might sell for less. Being a bit of a "woob" (wireless noob), I might have overpaid though :)
Btw, I am assembling gear for a 11a backbone. If anyone has a 5.8gig directional (panel or grid) antenna they are willing to sell, I'd be interested.
Cheers,
Sweets

Used Cards
I wouldn't buy used cards especially high powered ones as you don't have a return policy or warranty.
Also high powered cards can be damaged simply by powering them without Antennas.
These cards can also be effected by being powered on then not being switched to the correct antenna in software or water getting into coax or a faulty or poorly designed antenna.
Just a few things to watch out for :)
I know the seller, they are
I know the seller, they are part of the Bendigo Wireless group.
The cards are tested and working, there is nothing wrong with them.