Wjile running a node is basic thing anyone can and should do I would argue that it is rather 200-250 USD at minimum.
I would not recommend for a friend starting this journey anything like Raspberry Pi unless he likes tinkering or is masochist. So any x86 old laptop or miniPC with i5 chip + 16GB RAM + 1TB or now rather 2TB would not make 150 bucks. At least I could not see anything worth a try.
I’ve got Ronin Dojo running on RPi4 and when it is working it is brilliant but when it fails it is most of the time full breakdown and requires reflashing and lots of time to bring it back to life while Start9 on miniPC just works.