Welcome to Pinside. While there are a lot of great people here, there are a few scoundrels too. Keep an eye on the Ca for sale thread mentioned above, there are good deals every so often. There is also a few "flip and rip off your fellow pinheads clowns" on there but they usually get outed pretty quickly. If you are like me, the character of the person who is selling the pin is just as important as the pin itself. I won't buy anything from these "flipper" guys despite how bad I want the machine. If you question a seller, click their forum activity and see how many games they post for sale. That's how you can find the flippers vs the collectors. If they are posting machines for sale frequently, probably a business transaction and I'd shy away. Good luck, ask lots of questions, and enjoy the ride!
Chris
P.S. You're in Riverside, here is your first tip - beware of Corona/Eastvale.