• Pi Zero Kit - $37

• USB Controller - $17

Total: $54 + tax

Round it off to $60 with tax, and I'd say that is around $50 since I didn't pick the absolute cheapest options. I'm certain that the $50 price point is more for people who don't have to pay online tax. This is basically the minimum needed to get going with RetroPie, and unless you are trying to do PSX, you really don't need the Pi3.