Thermo Hygrometers

I've only had this car for a few months and I've had so many problems with it, but the funny thing is that things always go wrong when it's raining. Every time I've brought it to my mechanic, though, he claims it's a new problem. So far he has changed my crank sensor, my spark plugs, an ignition wire, and once he even told me that "nothing was wrong" except a gas station attendant not turning the gas cap enough times. I've put about a thousand dollars into repairs and it just crapped out on me again; this time, instead of stalling like it had done for most of those problems, the engine isn't even trying to turn over. Just complete silence when I try to turn my key. I knew I was going to have SOME issues because it was an "insanely good deal" from a dealership going out of business, but I feel like this is too much. I also feel like my mechanic is screwing around with me. Anyone have any advice for me? I haven't been driving long and I don't know a lot about cars.