Jennifer 7097

HI. For the last few months my truck wouldnt start sometimes but after a few turns, it would start. Now, it is completely dead. I have tried getting a jump, wouldnt start and have it hooked up to a battery charger and it says battery is charged, still dead. I have checked the connections and the wires. I am at a loss. I have had 2 mechanics out to look at it and both gave completely different answers and wanted a ton of money. Thought I would try here. Thank you in advance.