Wow, I thought I saw everything... But people on Hot Deal board berating someone because he is being too cheap? Will wonders ever cease?
If I do it in B&M, I usually go for the copy machine charge (unless I really do need something or they have cheap junk on clearance table). It is 6 cents a copy, and you fill your own slip on how many copies you made.
As was mentioned, MSN CDs are 1 cent, so they are good for hitting the limit. Rubber bands is another good one (don't have the SKU with me, but should be easy to find).