This DIY Raspberry Pi Gameboy, published by adafruit, an electronic device DIY and sales site, shows how to build a Game Boy-like handheld game console using a 3D printer and a Raspberry Pi. The parts required are a 3D printer, a Raspberry Pi, and a Game Boy-like handheld game console.

The parts needed are a case made by a 3D printer, Raspberry Pi Model B, a lithium battery, and a game console controller.
Parts required other than the main case】
・Raspberry Pi Model B
・PiTFT Mini Kit
・GPIO Pi Cable
・PowerBoost 500
・Micro Lipo Charger
・SNES Controller
・2200mAh lithium 2200mAh lithium cylindrical battery

The controller seems to be disassembled to use the PCB and buttons inside.
Assembly and programming instructions can be found at adafruit, and all necessary parts can be purchased. 3D data for the body can be downloaded from the 3D printing community Thingiverse.
Is it cheaper to buy the materials and labor? No, this is what DIY is all about, isn't it?
All images are from adafruit.