I don't really want to pay for my games, as I don't have the money, so are there any games that are downloadable, either FPS or RPG and are free? No illegal stuff please.

 

inb4don'tbeatightass.

I would suggest going back through old games that are cheap now, or that you might already have, and downloading mods for them. A good example is Morrowind, with mods you can probably play that game for 10-20x longer than without, and it was already a 100 hour game if you do everything.

 

The only free fps game I can think of is assault cube, but I'm blanking right now.

Urban Terror

 

Pretty good open source first person shooter. It has that crazy quake 3 jumpy stuff, a strong sense of realism (apparently), always people playing, a wide variety of game styles, a nice selection of guns; should keep you quite entertained for a while. It does the trick for me.

Are you looking for online or single player?

I think this belongs in the game recommendation thread, but in the meantime, I really don't think there's a whole lot you can do for free. Like Doom said, try modding a game you already have.

 

Or do you have any Source games? This idea will require you to spend about $10, but I think it's well worth it for all the content you could ever need.

 

http://www.garrysmod.com/news/