I want to engourage you to build your own driver. But buying the parts by the piece will cost more than a complete built driver. You will also have to learn to Flash the Firmware to the MCU. The flashing parts can be had for under $20 or even under $10 if you go with a made in china clip.
Guide: how to flash ATtiny13a based drivers (NANJG, QLITE, etc.) with custom firmware
That is a basic guide on the 13a MCU but for the ramping UI’s you will need the 85 based chip. It gives you an idea of what to get and how to start flashing. And that there is a little more than just assembling the drivers.
If you intend to build more than one I say do it. But it is an investment compared to just buying one already done. For some, just installing the driver is a tedious endeavor. Building a driver and just laying out the tiny parts takes time and gets frustrating but I kinda enjoy the challenges.
I have recently started building my own drivers but I am fortunate enough to be in USA and MtnE is only a couple days for shipping. His parts are reasonable and I can build 2 for the cost of one assembled driver. He also sells the MCU only with some UI options already flashed.
I believe you will still need to order the boards from USA. OshPark is where the files are shared and orders made. I forgot that part… On OshPark TA lists the parts needed and some have a shopping cart build link to an electronics supplier.