You get it using Pandora's battery or downgrading, depending on what firmare you are on now. It is worth getting, as you won't have to pay for any more games. You don't need it to play PS1, but to get it on official firmware, you need to buy them through a PS3, or, the PS market on PC that the have now.
You never have to buy games ever again, you can play retro consoles up to N64 via emulators, and run free homebrew games and applications, such as IRShell, which is a multitasker, allowing you to play your music in your games.
You will find you can also sauter your battery. I don't reccomend it. There are so many things that can go wrong, youd be better off to just buy that battery linked above.
