Good ideas for a legitimate buyer, but in this case it's clear he's not one of those.
Update: I found out some more about the scam here:
http://scam-detector.com/auto-scams/...ry-report-scam
It's not as bad as I thought. That is, they're not trying to get my credit card number. Instead, vinjunction.us is just a redirect site. Going there takes me to vinjunction.com, which apparently really does give vehicle history reports. The scam is that by using vinjunction.us, the guy who emailed me gets a commision for sending business to vinjunction.com. Once he finds out I got the report, he'll back out of the deal, since he got his couple bucks.