94 Grand marquis starting problem

I need help figuring this problem out. Sometimes when i go to start the car nothing happens, no crank, nothing, I have no power at all. Then i mess with the battery wiggle the cables and the car starts up, its been doing this for awhile. Then last week i was driving down the road came to a stop and the car went dead, did'nt sputter or anything, just died. I turned the key nothing happened tried a second time and the she started right up. Lost all my radio stations. Then yesterday drove for about twenty minutes everything was fine. Stopped at the store, when i tried to restart, nothing, dead. On the second attempt heard the starter trying to engage, tried a third time and she started right up, lost my radio stations again. Could this be a starter issue? Alt and battery only 2 years old, cables are tight and good. Just trying to pinpoint the problem without having to spend too much money.