Classified Ads / Registration

I'm running an extremely tight budget but I am desperate to find either a flash/xml/php script / app that will allow users to register to my site and upload descriptions & image in order to advertise on a separate page on my site in a 'Classified ad' type format. I'm ideally looking to have s system whereby people pay on registration, thereby allowing them to upload images, to be used in adverts on the website. I can implement payment facilities but if it could all be integrated into one single script/app then it would help me a lot. I'm looking at something in the region of £20-£40 GBP Here's hoping!