1998 Buick Regal won't start-just makes one click

My 98 Regal won't start. A couple of months ago I trouble starting it and it made repeated clicking sounds. I took it in and got the battery and starter motor connections tightened up-everything worked great. Now, one week later it won't start at all and only makes one click. I've tried jumping with no success. My interior lights don't dim when I try it to start it so I didn't think it was that anyway. I'm in college and pretty broke so I can't really afford to fix the wrong thing. I heard something about my key maybe shutting down the fuel system but I don't know much about cars. My first thought was starter. If it does sounds like the starter, is it something that I could put in by myself?