1999 Other Jeep Models ughhhhhhhh

I thought my car was not starting because there was some corrosion on the battery. I would turn the key and it sounds like the car is turning over but it can't get to the point where it fires up. A few days before the car didn't start completely, it was struggling to start. I would start it, and then it sounded like it turned off for a moment, and then the engine would slowly start to idle. I know it's not the battery because I can still listen to my radio and I have a full tank of gas. I had spark plugs replaced maybe 3 years ago so I don't think it would be them either. I had experiences a while ago where I would be driving and the car would just. Turn off while I was driving down the road! I paid a lot of money, and then my mechanic friend replaced this tiny snake looking piece and it worked after that! (So far). I'm wondering if this is something simple, or if I should just get the car towed to a shop.