Anyone can upgrade an ad. Besides, you can always win one of the prizes by having the top 10 Power Indexes. That has nothing to do with bonus plays. You can always redeem your bucks for stuff too.

It's a free game. You can play it if you want or not, but it's designed to both reward members at a fun game and drive additional business for the site. Since no member has anything invested, we will continue to reward those members who support the site.

Hope that helps explain it.