Not sure if these are any good:
$19 -- 512MB CF (kingston @ buy.com)
http://www.buy.com/retail/product.asp?sku=...45&loc=101&sp=1
Kingston is a good solid brand IMHO.
Please note: The rebate allows you to buy TWO and submit both rebates on one rebate form (with 2 UPCS) and get twice the money back. You cna still do it with just one, but this way you snag two and dump one on Ebay or give as a gift...whatever !!
Also, Kingston is great about rebates too...never a problem and I have done at least 5 (that were all for two items).