I have a server at home instead of a PC... bin like 3-4 years old now.
HP ProLiant DL160 G6 Server 2x Xeon X5650 Six Core 2.66 GHz, 48 GB DDR4 RAM, 2x 1000 GB SATA 7.2K
Costs around 275$. It can run 50 bots without a problem.
Maybe even 75 with low cpu mode and a very simple script running
10 bots atm: (Note that teamviewer and Botmanager are running aswell)