Baby/juvenile beardies are simply expensive to feed. You can minimize it by providing a variety of feeders, but there is really no way of getting around the cost. I've been spending about 80-120 USD per month on dubia roaches alone. I bought adults for breeding, but they can't produce quickly enough to keep up with Oscar's appetite. This is even with me supplementing him with hornworms and wax worms as treats. Right now he is eating about 30-40 per meal, and he eats twice a day. So 60-80 roaches per day is about 1800 to 2400 per month. It's just going to be expensive, unfortunately.
They will definitely eat you out of house & home! Where are you buying your dubias?
Try to supplement with worms as much as you can, it is difficult when they are growing!
Starting your own is a great idea but does take some time to get it going.