The Ubercart Userpoints Discount module makes it possible for customers to add items to their shopping carts that are discounted based on the number of userpoints they have. Discounts are enabled for individual products on their node edit forms, causing a second submit button to be added to the product's add to cart form that adds the product to the shopping cart with the discount. The value of userpoints are specified as a conversion rate against the dollar (or your store's currency) in an administration form.
This module should not be confused with a full Userpoints integration. This module requires Ubercart to run!
This module alters the cart view form so a customer can see their discounts before proceeding to the checkout form. During checkout, discounts are represented and added to the orders as line items. A customer's userpoints are held while the item is in their shopping cart so they can't get more discounts than they deserve! These will expire if checkout is not completed, or they will be permanently deducted from the user's account when checkout is completed.
Again, this module provides no Userpoints integration beyond the ability to purchase products at a discount with userpoints. Its scope is limited to the functionality as described above.
Module sponsored by the folks at http://www.horseracegame.com.