When you buy a banner ad, is it customary to charge more?

I was wondering. I know when I get an eros call it's more. It just kind of doesn't make sense because anyone can be "VIP" or buy the top advertising spot. I think it's good for traveling to stand out but does payment differences come into play?

The more imp question is :

In 5 months that you have been a member you have 3 fake yes reviews and only one genuine review , which is of course a "no "..

Why is that ?