Symbolism, Imagery, Allegory
A couple of days before Christmas, Crash realizes that he hasn't bought a present for his grandpa Scooter. Suddenly, he's overcome with the superstitious belief that if he doesn't get Scooter a gift stat, the old man will perish. (Kids will be kids, right?)
In a blind panic, he runs into the first store he sees and grabs the perfect present: red glitter heels. Just what Scooter wanted, we're so sure.
To Crash, the gift itself doesn't matter; it's getting the gift that's important. Because if he gets Scooter a gift, it means he thinks he's going to live. And if he doesn't? Well, that would mean he'd already given up hope.
So, yeah. The shoes = faith, hope, and the belief that Scooter will recover. Still, you have to admit it's a little bit hilarious that he goes for high-heeled shoes. Correction: glittery high-heeled shoes. It's a bold choice from a guy who's been making fun of "Little Miss Webb" for being a male cheerleader.
And, of course, the heels come from (where else?) the thrift store that Crash has vowed he will never set foot in. Thus, the shoes could also be seen as a symbol of Crash's changing priorities.