Sometimes those are 10K gold. Modern 50 centavo today here. Very small. Smaller than a dime and thick.
I have gotten a few of those receipts that people have left behind, a nickel,(sometimes more). And cashed them in. One time the coins were trapped in the grill acceptor slot and I couldn't get them out. So I dumped them into the machine, turned it on and got a receipt for 12 cents.
The most I ever got from a discarded voucher was for $12.58 at a Publix. I found it sitting under the machine along with a few foreign coins.
I found an Israel new shekel in the reject bin at the wal-mart on the Latino side of town. 1 new shekel converts to 28 cents.
I was approaching a CoinStar this evening when a teenage kid swooped in front of me and scooped a handful of change out of the reject slot. He then stood there, carefully examining each side of each coin, while his mother fussed at him that they needed to go. I'm glad they went to a good home. If not for the creepiness factor, I would've asked him what he found...
I would have asked but first I would have told him that he was smart for checking his finds then introduced myself and asked. but that's me