This reminds me of a story: For a certain time in recent theory you were able to legally "print money":
A couple of years ago when Germany got the Euro currency there were put a few regulations in place for the banks. If you came to them with 100 Deutsch Marks in your hands (old currency) they had to convert the 100 Deutsch Marks to euro by using the ratio 1:1.95583. The banks had to round up if needed. So in theory you could give them 1 Pfennig ( = 1/100 of 1 Deutsch Mark) and demand that they exchange that to Euro. If you do the math 1 Pfennig ~= 0.5 Euro Cent. Since the banks had to round up you ended up with 1 Euro Cent. That is a 100% return of investment. Now in theory you would have to give your bank 50 million 1 Pfennig coins (separately) and you would have gotten back 100 million euro cents = 1 million euros. But you would have only invested only 0.5 million euros. And so on…
I am not sure if this is an urban legend. It was told to me when I was a kid.
The reference is to an episode of Seinfeld where the Kramer sub-plot is about bottle deposit returns. Kramer notices that he can get 10 cents instead of the usual 5 cents for a bottle deposit return if he can return it to Michigan. Newman says that it can't be done, he's crunched the numbers and you blow all of your profit by transporting the bottles (remember, Seinfeld is set in NYC). However, Newman (a postal worker) finds out there is an overflow mail truck that only happens on Mother's Day due to all the cards that are sent and that they can have the USPS essentially cover the transportation so he signs up to drive the truck. Of course nothing goes the way it's supposed to when the Elaine/Jerry plot merges with the Newman/Kramer plot and Kramer is forced to abandon the attempt mid-quest (after throwing Newman out of the postal truck) to recover JFK's golf clubs.
The picture is of Newman drinking a soda so he can get the deposit on it.
There's a somewhat similar actual occurrence. It turns out that retailers get something like 7 cents a can for soda bottles, but the way the deposit law is set up they only have to pay 5. I guess it's to encorage them to collect the cans. Anyway there's one store in Brooklyn that started offering 6 cents instead of the usual 5. Apparently there are lines around the block and people using the machines 24/7.
Around here (SF Bay Area, California) we pay the "deposit" but none of the stores (I'm aware of) actually buy cans and bottles back. I'm not sure how much the per can price is at the recycling places you have to take them to.
I was very surprised one time on vacation in Oregon when there was a can/bottle recycling machine right at the entrance of a grocery store. I walked back to it with an empty can from the car I had and fed the can into the machine. I was a little disappointed that all it gave me was a receipt to use toward my next purchase at that store. But if it was a store I went to regularly, it would totally make sense.
I live in Oregon and you can get cash from the store for that receipt. Some people (homeless, poor, frugal) collect bottles and cans from public trash bins for this exact purpose. Sometimes schools have fundraisers where you drop off bags of cans and then they take them in and get the cash value for them.
Yes, well... Funny story, but a slightly mentally unstable guy in Queensland insisted on paying for a bag of mushrooms at his local supermarket mushroom by mushroom. They disallowed it, so he left and entered the store 40 times.
The reason? The scales weren't terribly accurate and rounded down. Each mushroom came to 0.48 cents, which because they rounded down came to nothing. He got a bag of free mushrooms. And a lifetime ban from the store.
A couple of years ago when Germany got the Euro currency there were put a few regulations in place for the banks. If you came to them with 100 Deutsch Marks in your hands (old currency) they had to convert the 100 Deutsch Marks to euro by using the ratio 1:1.95583. The banks had to round up if needed. So in theory you could give them 1 Pfennig ( = 1/100 of 1 Deutsch Mark) and demand that they exchange that to Euro. If you do the math 1 Pfennig ~= 0.5 Euro Cent. Since the banks had to round up you ended up with 1 Euro Cent. That is a 100% return of investment. Now in theory you would have to give your bank 50 million 1 Pfennig coins (separately) and you would have gotten back 100 million euro cents = 1 million euros. But you would have only invested only 0.5 million euros. And so on…
I am not sure if this is an urban legend. It was told to me when I was a kid.