2003 Dodge Caravan cant get it to start

I received a 2003 dodge caravan as a gift. It sat for a while and needed a jump to get it home. After inspecting it I realized it would need some work so it sat for couple weeks while I got the parts together. Again the battery went dead so I tried jumping it. Three times in a row it started right away and then died after the tird time it stopped cranking and just clicks at the starter relay. I have tried to reset the computer by disconnecting the positive on the battery for about 20 min. Still nothing, so I jumped slots 30 and 87 in the starter relay circuit and the starter cranked so then I bypassed the park neutral switch and still no crank. I am stuck at this point. What could be the problem.