Place the graham crackers into a plastic bag and use a rolling pin to make fine crumbs. Pour the crumbs into a bowl and add the sugar and melted margarine. Stir well. Pour the mix into a pie pan and use your hands or the back of a large sppon to press the mixture into the bottom oand sides of the pie pan. If you need to pre-bake the pie crust, bake for 8 minutes at 375 degrees. Otherwise, chill the crust before using.