I lied, i have one more minor horror story with buying too. I bought my rMBP off of ebay for a pretty good price. A few months after I bought it, it stopped booting and would show a grey screen with a question mark on a folder (means there is no boot drive to load from). When I took it into the apple store, I found out that this laptop had been dropped right before I bought it and had to have like $1500 worth of repairs as it was having the same problem.

So not only do you have to worry about scammers, you have to deal with a market for lemons [1]. (Quite ironic now that I think about it as that is one of my favorite economic articles)

[1]: https://www.iei.liu.se/nek/730g83/artiklar/1.328833/AkerlofM...