Your site is easy to rank top 10. I would charge $1000. The problem here is the only way to make this site rank top 10 is blackhat. You will be top 10 for a month tops and then get banned from google. Is it worth top 10? Invest the money in developing a site with content that gets updated daily or semi daily that is unique. If you do not, then this site CAN NEVER become top 10 on google without a ban. THis is a fact.