this was very useful and relatively easy to set up
I needed a way to allow users to sign up/register for a class and pay for it through Paypal. This worked exactly how I needed it to.
You can view what I did at http://www.ncdancesport.com/register
I am a novice/hobby Drupal user (love it) and this was relatively easy to understand for someone with about one year's worth of Drupal knowledge.
I searched around for a way to do this task and know that there's a signup pay module and pay for a node module and other similar modules, Ubercart Event Registration but after testing them, using UC_Signup and the following modules worked the best.
Free Order (to sign up for free classes)
Discounts module (not the uc discounts alt)- allows early bird discounts and single or bulk coupon codes.
I took off a star for not complete enough documentation and also took off a star because I was hoping to have an easier time with Views to get the reports that I need. Maybe it's my inexperience here, but I HIGHLY RECOMMEND this.
Just test it and test it a lot before going live. Get a developer/sandbox Paypal account and go through many iterations to see how this all works. Test it some more in any scenario that you can thing of and try to break it.
Note that ubercart creates accounts with login and password automatically and there's no way to seem to stop it, but oh, well, you can block the users from tinkering.