The best prices for live silkies are at silkwormfarm.com , but mulberryfarms.com is also good and has the best price for food.
I persoanlly say breed them. They are EXTREMELY easy to breed, the moths dont fly or anything. And it saves you on $15 of food every 3 weeks as well as the high price for the worms. Silkworms can grow about 4" and the width of your index finger, and have virtually NO risk of impaction (of course I wouldnt feed a month old a beardie a 4" silkworm, lets use common sense when feeding
The thing about silkworms is still price, thats the killer. They only eat mulberry leaves or special chow, and that chow usually cost about $10-15 every 2-4 weeks. But they are a much healthier insect. They are plump, even stubborn eaters will go for them, and they cant hurt the beardie in any way. Plus they virtually have no odor, cant escape from the conatiner they are in, and they are kinda cute!