Advertisements are less about leading members to another community and more about affording paying customers with a chance at increased traffic for their own community, while providing revenue for WebFlake. There's no guarantee of clicks much less permanent residence at the advertised site and since we aren't going to permit the submission of sites that are similar in nature to WebFlake, it poses absolutely no risk to us.
Price is based on market value and is much more competitive than peer sites. WebFlake is averaging nearly 6k unique views per 24 hours with a sub-5% bounce rate in that same span. Great numbers for a site that has been declared "dead" by its competitors.
As for why there is a price hike for the monthly term, it's to prevent a monopoly on adverts. Submissions are placed into a first come, first serve queue and will be rotated frequently.