Quantity   Component name
1 × GOOJPRT QR203 58mm Micro Receipt Thermal Printer RS232/TTL Compatible +EML203 printer core; serial 'TTL' interface. I got mine from eBay from China for USD$ 18, free shipping. The source also supports the 'Kashino' (e.g. the kind from SparkFun or AdaFruit), and an APS model. The printer support is modular, so you can add a new one relatively easily.
1 × STM32F103C8T6 ARM STM32 Minimum System Development Board Module so called 'Blue Pill' development board; I got mine from eBay from China for around USD$ 2.25, free shipping
1 × Vishay TSOP4133 IR receiver; I got mine from Mouser for about USD$ 1.30 It must be exactly this model number, because of AGC characteristics.
1 × FT232RL 3.3V 5.5V FTDI USB to TTL Serial Adapter Module this is just needed once for the bootloader to upload pre-built firmware; these are about USD$ 2.50 from China. I keep a handful of these around.
1 × Power Supply; regulated, 7V, 3A Yes, you need a hefty power supply for the thermal printer. It's not about voltage, it's about power when those heaters fire. Weaker power supplies will sag under the impulse load, and you'll reset your controller board. The degree to which this is true varies by printer model, but I recommend not going over 7v to avoid stressing out the linear regulators on the boards.
1 × Development Toolchain I'll describe this more later; you only need it if you are building from source. Short story: free tools from ST, STCube32MX, System Workbench, ST-LinkV2.1, etc.