Extension request for pay to post

[derold]

I was wondering if it was possible to create an Extension for pay to post. Like a classifieds ad. I was trying to use guest book with pay pal and a redirect but that did not work. I have a site that deals with one topic like tree services by state. when a person places an ad it would list it one by one like in guest book. I would add a new book to each page for each state. but I want them to pay before they can post. I have a frend that wants to sell baseball cards. he wants to let people sell there cards on his site one dollar to post your ad. I cant figure a good easy way to do this.