My first mower was my Dad's. He was getting a new one, so I got his old one. It was the one I used to use to mow his yard, so I already knew how to use it.
If you don't like shopping or don't know where to start, just wait till spring and walk into any home improvement shop. They'll have mowers everywhere and you can take your pick. Pick something cheap. Once you get it home and decide you don't like it, you'll have a better idea of what you liked and what you didn't like, and it will help you know what questions to ask the next time.