Newegg.com has this A-DATA 8GB Secure Digital High-Capacity (SDHC) Flash Card Model Turbo SDHC 8G combo for $10.99 after $5 Mail in Rebate.
Original Price: $20.99 - $5.00 Instant rebate =$15.99 -$5.00 Mail-In = $10.99 + Free 3-7 Business Day Shipping
See below for an additional $5 rebate for a total price of $5.99 (Thanks Deshwasi)