Q: Difficulty starting my vehicle for a couple weeks until it would not start at all.

In July I brought my vehicle for a tire replacement and got an oil change at the same time. The next time I drove my vehicle, after my first stop, the vehicle would not start. Over the next two weeks, I had progressively more difficulty starting my vehicle and eventually required a boost every time it sat for more than a few minutes. I returned to the original shop and asked if they could have done something or knocked something loose because their paperwork indicated that my battery tested fine. They performed another check and said my battery needed to be replaced. I replaced the battery. At the beginning of October, I started having difficulty starting my vehicle...again. It took three to five attempts to start my vehicle, but I never required a boost. Tonight, I drove about two minutes prior to my first stop, then could not restart my vehicle. The lights and power windows worked. Attempt to boost did not work. Does this sound like I need a starter? How much will that cost me!

My car has 120000 miles.
My car has an automatic transmission.