Find a collector friend to go with you. He can help guide you so you don't get the first game at any cost fever.
Then the hobby will be more enjoyable for you and you'll have more fun. Go to shows, meet people. All can be sources to help you.
When looking at a game. First thing I check is the hard to clean places. If they are clean, the machine has been maintained. Also look at the boards. Repairs are okay as long as the right parts and tools were used.
Don't buy problems for your first game.
Unless you have unlimited money and like the smell of burning electronics, then drag home anything you want. It will be an adventure then.
LTG : )