Forum Moderators: buckworks
First of all welcome to Webmasterworld.
I don't belive there is a simple answer to this one because there are a lot of different factors that determine how much you can make selling adverts.
The easiest way for you to do this would probably be to set up an account with one of the third party advert serving companies such as fast click, burst or trade doubler there are many more but I just used those as an example.
The benefit from using a third party provider is that you do not have to do any of the selling. The adverts are served from the companies server and you get payed either per click or per action. There are still a few companies that offer cpm (cost per thousand impression) but these companies appear to be few and far between.
If you do decide to sell your own adverts then the price will really be determined by the industry or topic of your website. Your traffic levels and pagerank may also play a part on deciding how much to sell your add inventory for.
Quite often I see sites that simply sell text adverts on a monthly fee. I supose this makes it a lot easier for the publisher. The only draw back is that in some cases it is better to have a set price per click from an advertisers point of view.
Hope this is of some help.
Mack.
Here is a recent thread that may help you:
Feasibility of advertising revenues [webmasterworld.com]
Good luck!