Frederick is making popsicles to sell and to save money he is making his own popsicle sticks. He can get 200 sticks from a 2 x 4 piece of wood and 400 sticks from a 2 x 8 piece of wood. He has $24 to buy wood for sticks. A 2 x 4 costs $4. A 2 x 8 costs $6. What is the most popsicle sticks he can make if he buys the cheapest lumber?