Before you go on to Bob's page I wanted to make mention of a couple of things. Bob has been helping the arcade community for many years, and he is one of the best sources for parts in general.
However, don't go there expecting a high tech glitzy site where you can put a bunch of items in your shopping cart and pay by credit card.
Bob runs this out of his house, and to keep costs down he keeps it very simple. When you find what you need, email Bob and tell him. If you can't find what you need email Bob and ask him. He will email you back your information and give you a total.
Send him a check or a money order, and via Priority Mail, your package will arrive in a short time. He does not take credit cards or PayPal. It may seem like a strange way to to business for those accustomed to Amazon-esque retailers, but I would rather deal with Bob than any other.