If its a trusted seller that has references... I personal think a direct bank transfer would work. But you need to do some research on the seller, there are alot of scams out there and once that direct bank transfer is made, say goodbye to your money cause it won't be coming back.
Paypal works well but there are also extra fees involved both for the buyer and the seller. Of course with those extra fees you get buyer protection and would have a very good chance of a refund if something went wrong.
As far as shipping. Probaly best if the seller can fix it, just remember not all sellers are capable of packing a pinball machine well. Wouldn't be fun getting a game with a smashed up cabinet or broken glass. If your a private person it seems extremely hard to get one of the major shipping carriers interested in helping you.
Just be careful, what you see in a picture might not exactly be what you are paying for....