I'm creating a site for a local retail shop using Drupal. Everything's been going very smoothly up until this current bit.

It's a comic shop, and I want to make a place where people can manage their own subscriptions. Since the number of different titles a customer subscribes to can vary pretty widely, I want a way to make a completely dynamic form, with people able to add as many new lines as they need and I'm really struggling with Drupal's documentation.

Essentially, I'd like the final version of the page to look something like this: http://www.monksp.org/foo.html

Anyone have any experience building a drupal form like this?