What is the difference between buying one from LFS.net or buying one that somebody has already used? Just go buy one on LFS, it isn't like you are wasting tons of money or taking a gamble on this.
I love S2, and the fact that the game isn't just some one-time purchase and you aren't stuck with a crappy game makes this game shine. Buy S2, and you'll get updates and patches for a long time. Heck, when S3 comes out, you would get the updated material, just not the S3 content (which would be like cars & tracks). People don't seem to understand how much of a value LFS really is when it comes to buying a license. You really only need to buy your license once and just keep on getting updates and free goodies. And if you become active enough in the community, it is fantastic.
Hardly anyone sells their license to someone, they'd mostly all give you support and tell you to buy your own, it is worth it.