I bought this game 2 weeks ago at FYE for $50.Its an amazing game,I beat it on the hardest setting and it was quite a task.
$30 and its yours.
Did you uninstall it as well? There are all sorts of DRM issues with these, you wouldn’t want to screw anyone one the sale. If you don’t/didn’t uninstall and deactivate, then you are using on the installs that is allowed. Depending on the print date for this copy, there are either 2 or 5 installs allowed. I’m not sure how much of this has been cleared up yet, but it is worth looking into.