Listing review fee price

Hi All DP Users,

Ok, It may be a strange question to ask and i know it depends on so many factors, My business directory is doing ok, Not sure how accurate alexa traffic stats are but its saying around 900,000 worldwide.

Trying to find a happy medium for fees, Large percentage of suggested submissions from SEO companies, Some from Company owners, I know it's all about what value my directory can offer but just trying to think of a fair price for regular yearly business listings.