payment for site registration

Hi Everyone, thought i'd post this here after the last topic of ecommerce and see what the drupal ireland community thoughts are

I have recently installed the premium module to explore restricting content to content types by role. This functions fine but I would like to now explore charging users to register on my site. Is the ecommerce module the only way to do this, it looks quite intensive to start getting into or is there a simpler method to charge users to register via paypal?