Web servers

christmas and my birthday are coming up and im looking for something to be used as a webserver. Im trying to use my computer as one right now but with around 450$ coming in, id perfer to get something else to run a server off of. I think a basic server is what i should get, but my dads friend told me its better to use a desktop, my dads willing to search for a used one but im curious whats better for my money. a computer or a server?