You can get your in-park purchases delivered.
If you're staying at a Disney resort, you can have your purchases from the parks delivered to your hotel so you don't have to carry them around. Another option is to have them delivered to the front of the park for you to pick up on the way out. You can even have your packages shipped home for you. Most people know about this, but what you may not know is that there are time limits on this. Package pickup stops running through the parks based on the gift shop's location. Because the parks close from back to front, package pickup also stops from back to front. But if you ask a cast member nicely, they might be willing to run a package to the front of the park for you to pick up later. I did this for more than one guest who purchased a huge stuffed animal at the Muppets store and didn't want to carry it to Fantasmic! As is Disney policy, cast members will go out of their way to make sure your visit is practically perfect (in every way).