You can use dried beans to weight down the crust of the pie or even a cup of rice. If you are going to bake pies often it is a good idea to buy pie weights. These are bean sized ceramic or metal weights and are sold in 2 cup packages for around five dollars.
Line the inside of an unbaked pie crust with aluminum foil and then place the pie weights on top of the foil. Bake the crust for about 10 minutes, then remove the beans or rice and finish baking until the crust is golden brown.