I'm looking to create a customer complaint-style site. That's not exactly what it will be, but should give an idea what I'm looking to do.

I need to be able to charge a small fee for listings (payable by credit card and/or Paypal) and have some email notification functionality.

So I guess what I'm looking for is something like a paid classifieds site but tailored more toward the listing itself and not for a product or item for sale.

I'd prefer a free and/or open source solution but don't have a problem paying for something if it suits my needs. I'd also prefer something done in PHP or AJAX but could probably manage with something in ColdFusion or ASP.

Any help or direction would be very much appreciated.