My advice when buying from anyone you don't personally know is to assume they are a scammer first and only send money once you've completely ruled that out. Then be really, really sure you both agree on what the condition is of the game and don't take words or terms like "the best playfield I've ever seen", spotless, like new, etc. and assume that your meaning of that term matches the sellers. If you get close to a sale it might be good to post the sellers name here on Pinside to see if anyone knows them or has dealt with them in the past.