Snapfish has 25 prints for $1 with code JUL4PRINTS. Sounds like you've got to pick them up at Walmart though, which is great if you've got one near you.
"Must use coupon code JUL4PRINTS to get 25 4" x 6" prints for $1 at Walmart. Offer good for first 25 prints only. Additional prints will be billed at regular price. Must order online and choose in-store pick-up at Walmart. All taxes apply. Offer applies to U.S. customers only. Offer may not be used in conjunction with any other offer. Offer expires 7/05/10."