How does one set up his own local server for free with MySQL and LAMP?

Okay, so I'm kind of interested in making my old laptop a local server *For experience* But I want to know, does it cost money? Most Linux software is freeware, I know that, but do I have to pay to set up a server? If so, how much? If not, how do I do it? Have you tried doing? Any tips and pointers? What would a local server be used for? Can I store data on the local server? What things should I learn before I attempt to set up LAMP? Also, another thing, I noticed that when installing certain Distros, like Arch Linux, it gave me a choice to install over the network with FTP, could I make my laptop a FTP server? Once again, I'm curious and I want to do this out of experience, but I don't want to spend any money either.