Buy.com is offering a 1gb memory stick pro duo for $9.95 after coupon and mail-in rebate. This will work for those with PSP's and is a very good deal for a 1gb card.

The item is normally $34.95, but when you check out using Google Checkout, you receive $10 off purchases $30 or more. This knocks the price down to $24.95, then send in the $15 mail-in rebate and the final cost is $9.95. Free shipping is also available.

1gb memory stick pro duo - $9.95 after coupon/rebate
Sandisk Rebate form