Hi @MrSeven you can definitely do the course on a raspberry pi 4.
For the ethereum 101 course for example you can code the smart contracts on https://remix.ethereum.org/ it s a web interface that allow you to build and test your smart contract online.
If you want to mine you will need a good computer but to code you don’t really need one, js course, c++ and ethereum can be made on a raspberry 4 (you can use ganache to emulate a node locally and run a Js server to test your front end).
If you want to run your own node or do the gaming course with unity you will need something more powerful.
So to resume if you really don’t have money to invest start with a raspberry pi 4 (90$) plug it on your tv with an hdmi cable (the cheapest way ) it will be a bit slow but it’s ok, i run bots on raspberry pi and watch streaming on youtube with mine so it’s ok for the course.
Otherwise if you want something for the long term take a something like intel core i5/i7 for the Cpu,
4gb/8gb ram, 250/500G SSD and gtx 960 (or less you don’t need a good gpu for coding ) it’s more than enough.
I will focus more on Ram and Cpu, storage is interesting if you want to download the whole blockchain and run a full node