<<Some state laws require that coupons have a cash value at which they can be redeemed. Most manufacturers set the value of a coupon at 1/20 of a cent. At this rate the cost of postage to send a pound of coupons to the manufacturer would be more than their cash value.>>
Clever. Very clever. For most coupons, I don't think you could just take 20 down to the local store and get 1 penny. You'd probably have to mail them to the manufacturer or the headquarters of the store offering the coupon to get the cash value. And of course, if a stamp costs 34 cents, it's gonna be very hard to make anything in the end.
It would be interesting to blow a stamp or two to send a company a stack of coupons and see if they'd mail you a check for a few cents.