No, FindRetros doesn't sell advertising space.
Pages are ranked based on the average of votes that they have recieved over the past 7 days.
There are a few reasons as to why that may occur:
Manage Pages » Edit » Voting » Return URL
12:00 AM CST.
Page ranking is based on a page's average number of votes over the past seven days. If more than one page has the same average then are ranked by the number of votes they received today, and if they're still tied it defaults to user ID.
You may have incorrectly configured the API or you could be using a proxy service.