Preheat oven to 375 degrees F.
Roll the pie crust out into a 12-inch circle. Place the crust on a large baking sheet. Top the crust with apple slices and cranberries. Drizzle lemon juice over top. Sprinkle sugar over top. Pull up the sides of the crust slightly and roll over, covering the filling by about 1 inch.
Bake 20 minutes, or until the crust is golden brown and the apples are tender.