I think most Linux users see HIB as a form of activism or donation (specifically to show that games on Linux can be profitable) rather than as a purchase. Heck, I bet most people who get HIB games (on Linux or otherwise) never even play them.
I only play one or two games from most of the bundles, though every bundle I've gotten has had one or two that made it worth it. And like most other Linux users I've usually paid around $10. But I haven't bought any bundle that didn't have at least a game or two that I knew I'd actually play a bit.
