Just use gulag aka bancho and guweb if you want a really easy to setup server
https://github.com/osuAkatsuki/bancho.py
https://github.com/Varkaria/guweb
I have no coding expierence and have setup multiple of these
Though other type of servers can provide a more feature rich expierence
If you plan to buy from someone with 0 rep, no connections to anyone who does have rep in this community (Maple, Assist Games or Natsumi) prepare your money to be stolen lol