Additionally, if you're nice, some soda machines will let you get your change back if you opt out of a purchase. You can sometimes insert a dollar bill into the Giver of Life, and then proceed to press the "return change" button and be rewarded with 4 shiny quarter-dollar pieces clunking their way out of the change return slot.

This can be a bit of a gamble, however, as some machines will be nasty and refuse change after devouring your bill. It's up to you to decide which machines are the kind ones and which ones are pure evil.