Jenna May

Hi This seems like a really easy question but unfortunately I can't seem to find a simple, free(!) answer on the web! I am building a site which requires a user to pay to register for services. The way I visualise this is that they create their own username and password and are then requested to complete some payment details - paypal or credit/ debit card perhaps. Would be grateful if anyone could suggest a simple way to do this - particularly as it's been a while since I have coded any PHP! Thanks JM