Mix sugar, margarine and corn syrup in pan. Bring to a boil. Boil 5 minutes, stirring often. Remove from heat and add soda. Stir until light in color and foamy. Spray a roasting pan (deep 10 x 14) with Pam. Put Cheetos® in pan. Pour the mixture over Cheetos® and stir, coating each piece. Place in oven at 250 degrees. Bake for 1 hour stirring every 15 minutes. Immediately, pour onto wax paper, or cookie sheets, sprayed with Pam. (This is the hard part.) VERY QUICKLY spread out as thin as possible. If not quick and spread out as thin as possible, you will get a big hard glob. After about 5 minutes, pull/break these apart even more and loosen them from the wax paper. If you don't, you'll have wax paper stuck to them when you go to eat them.
You will regret it if you don't double the batch as guests are going to demand MORE! You can bake batches together and add an extra 20 minutes to bake time. I do them separately because of having to work so quickly to keep them apart at the end. The one batch can almost get too hard while working with the other batch.