Camera Woes

Well my old timey Nikon D100 has been out of service for a while. I think there may be a problem with the lens and or camera because it really doesn't like to get in focus and there is dirt inside the lens. I just called to see how much it would cost to get it serviced and the quote was $415. Holy crap! I would be better off getting a brand new Nikon D 3100 for $650. Which sadly I can't afford either option. I would hate to buy a new lens and then discover it is the camera that is the problem. Guess I am stuck without a nice camera to take pretty pictures. Boohoo!