$20 Decks!
Decks for Vintage, EDH (Vintage Singleton), Legacy, Modern, Standard, and many other formats all for the massive amount of money called 20 USD, yep, that is it.
Many players think that MTG is a pay-to-win game, to some extent it is, the more money you have the higher your chance of winning, yet still, the budgeted players can win, and building a deck that is as good as possible on a budget, building smart within said budget, will increase your chance of winning.
The following decks are tuned tightly to that budget, a few going around the $25 limit.