$5 credit at Fujicolor (gives 20 free 6x4 prints)
Join Fujicolor and they will give you $5 credit on your account. Since the 6x4 prints are 25c each, this gives you 20 free prints.
You need to be a new member and you need to spend at least $1 with them to use the $5 credit. The credit must be used before 01/05/2007.
There are other terms and conditions which I suggest you read.