Originally Posted by 3devious

A better option for a subsidized premium account might be for heavy posters with higher ratings to somehow be rewarded this way. That way, you aren't rewarding people who are only contributing traffic (not the good kind, but the kind your host dings you for) to the site. Users with high post counts and high thanks/ratings are at least contributing content.

Giving those people even a small discount would not only be an impressive act of good will but could also serve as a way to encourage the type of participation in this site that you probably want.