Here's a quick example that illustrates how to remove a few State/Province options from the billing and shipping panes of the Ubercart checkout form, as well as the order edit/create form. Please understand there are other ways to do this (like altering the united_states_840_1.cif file and re-importing). The hook_form_alter() method seems less permanent, so I favor it.
This is just a quick code example. Imaging you have an Ubercart attribute that has several options and you'd like to show an "As low as $X.XX" price on the frontend. Here's a simple solution. Note that if you wanted the lowest price across ALL attributes you could loop through each attribute too (instead of just looking at attributes[1]).
This tutorial is for Ubercart versions later than version 2.3. If you're using an older version of Ubercart, you'll want to see this example. This example is very similar, but accommodates the changes made to the template system in Ubercart.
This tutorial is for Ubercart versions earlier than version 2.3. There is a newer version of this example for Ubercart 2.3 or later.
In this post I'll show how to set up an extra token for use in an Ubercart template. This will require creating a custom module (because we don't really want to modify others' modules). We'll use a few different hooks to create the token, and then simply modify the template to include this token. This setup requires the token module (which is required by Ubercart), so make sure this is enabled!