you can host a server off of your computer or any computer for free with the right software and good upload speeds/ram/processor, though for security reasons I do not reccommend it. any machine with access to internet can be a server, though a powerful machine is recommended and hosting from home internet can have security risks from hackers. Also, hosting off of Linux is far better than Windows or mac.

Also you need a purpose for a server and a program to run on the server and do a bunch of port forwarding.