Just some thoughts that may help someone.
To get started I would recommend the Nano. You just need it , a usb cable, and the IDE downloaded. The Nano has a usb chip on the module. No hassle s about connecting.
The pro mini does not have a usb chip, but is otherwise the same. To use it you need a usb to TTL adapter. I bought an adapter with a FDTI232 chip and could not get it to work. So looked on the internet and found some of the FDTI chips are counterfeit and do not work , or do not work well. So I ordered a translator with a CH340G chip and that works. Connecting the TT L translator to the mini pro is done with five jumpers. Not difficult but a little more work.
Buying off Alli the translator module was $1.40 and the mini pro $1.25.
Dan