How much should we charge for ads on ecofirms.org - pr5 - 500-800 visitors daily?

hi, we're thinking about removing google adwords and start selling advertising space.

How much should we charge for small side banner ads on the home page and all the other pages (1000s). Would text ads be better in terms of revenue? Any suggestions?

Thanks for your help

 

I'd say $14.00 a month then maybe increase the price when the traffic becomes heavier.