Now, I can't say that this is true of all locations, but Safeway has those premade graham cracker crusts in two sizes on sale this week (until next Tuesday) for only $1 each. Now, you can certainly make them yourself either from pulverized crumbs or buy the prepacked crumbs but these (Keebler Ready Crust) are made from the same Honey Made graham crackers* you'd probably use anyway and are pretty tasty.
Now if you want to do something fancy with your crust (like add ground nuts or ginger or something) then this clearly won't work for you, and making your own crust is certainly easy, but the difference in taste between the premade crust and homemade are not huge, and if you like to experiment with your pies like I do, it is a great and cheap (compare $1 on crusts to the $4 box of crumbs/crackers you'd have to buy) alternative. They also have chocolate graham crusts on sale (don't get the Oreo flavored one-ick!). Plus they all have an expiration date of October or November 2007, so you can stock up for the whole summer.
*I am sure someone, somewhere makes homemade graham crackers with the express purpose of crushing them for pie crust, but really, who is that person?