I noticed that there is a USB FPGA for $89 at http://www.xilinx.com/products/boards-and-kits/AES-S6MB-LX9.htm. Will this work and how can I use this?
Spend your money somewhere else. That board will only mine at around 5MHash/sec and earn you pennies per day. Your electricity cost for the host computer will far exceed that (and no, a raspberry pi won't drive it, not without a lot of hacking to put together a custom USB driver).
BUT, if you really want to give it a try, take a look at https://bitcointalksearch.org/topic/official-open-source-fpga-bitcoin-miner-last-update-april-14th-2013-9047
