FRAPS is not the best solution nowadays. A lot of free alternatives exists, aside the in-game one that has been already suggested. Even Steam has a built-in framerate counter. Not sure why you are suggesting an old paid program there :\
I still think fraps has its place for doing framerate related stuff specifically, it lets you record min, max and average framerates and frametimes to a text file and that part is all free. Though there may still be better programs that do that stuff for free too, I'm just not sure.