Ask HN: Which of these non-computer hacks is better?

1) In middle school, I devised a simple cipher and gave a key to a couple friends to memorize. Using the cipher, we'd pass encrypted messages on a calculator which we were allowed to share in math and science classes. While our classmates were punished for passing notes, we continued to use our system safely throughout high school.

2) When I was still in college, newly married, and very poor, our apartment had some furniture but very few electronics. McDonalds had a Monopoly promotion where some menu items would include game pieces and at least $1 in store credit for Best Buy. The rules had no restrictions against using multiple 'Best Buy Bucks' in a single transaction.

I was able to work out a deal with some McDonalds managers that if I purchased a certain amount, they would give a few extra containers for free. Large fries were the lowest cost per game piece, so I would order 10-20 at a time and receive a few empty cases for free. We'd give what we couldn't eat to the homeless around Santa Monica, but kept the containers.

I kept all of the Best Buy Bucks and sold the unpeeled game pieces on Ebay. With the free cases, I would break even on the initial investment and repeat the cycle. When the promotion ended we had gained lots of free (albeit unhealthy) food and about $800 worth of credit at Best Buy that we used to buy some electronics we needed.