Yes! And on GiveGab, there are two ways you can do this:
Registration Types: When you create a registration type, you publicly display the different registration levels and how much each level is paying. This is great for things like Adult vs. Child registration fees, Walkers vs. Runners, or other self-identifying information. You may limit the number of registrants you have per type.
Registration Codes: A registration code is more secret, allowing you to send a code to a select group of people and having them enter the information as they register. This is great for offering free registration to a sponsor's registrants, or for $5 off for last year's event attendees.