There's a really really quick way to get any participant's registration receipt. Here's how to find it in the powerful Athlete Finder. Here's how to find it in Participant Details:
If you like to keep things a little more old-school, you can also go right to their receipt as long as you have their confirmation code. Just plug that code into this URL:
Replace [ConfirmationCode] with the actual confirmation code and, hoo-waaaa, you've got your registration receipt.