What can be wrong with a car that has a battery that is fine but car still wont start

My car wouldnt start when I went to crank it to go to work it seems like sometimes it wants to turn over then other times it wont even get that close to cranking it just clicks like the starters is bad ive replaced the starter battery and alternator one time all at once cause my battery that was in there when I got was the wrong battery so the alternator lost power and the starter died all at once and I replace all with jnkyard parts cause didnt have the money for all and now I have absolutley no ideal if two out of three is the problem or if it something else