Just buy your machines local,or within driving distance.
Order parts COD if possible.
Ask for references from dealers.
If it sounds to good to be true ,it usually is.
If anyone on EBAY wants to do the deal outside EBAY and uses there personal email,its a usually scam.

ohhh buddy do i have a story for you about COD.
ok so last year in may i sold my paintball gun to a guy in illinois. well he wanted to do COD and UPS was the cheapest to do COD with. so i went to UPS and mailed the $400 paintball gun. a week and a half go by and the guy still hadnt recieved my paintball gun(that is what he said). so i called UPS and they said it had been delivered. so wheres my money? well come to find out the damn kid at the UPS store forgot to put COD on the label so the UPS driver just dropped it off. so the guy says he never got the paintball gun but he really had. so months go by and i still dont have my money. finally after threatning the UPS store to go to court the guy that has the paintball gun sends me a check. i thought for sure it was going to bounce but it never did and i got my money.
this is something to think about if you are ordering something COD. just dont use UPS for COD or absolutely make sure that they put it on the label.