If you're in to building stuff and have tools. I'm pretty sure a cage could be built for well under 100 dollars. 200-250 is what the average first time builder spends. If you look on craigslist for building materials, you could probably get a 4x2x2 built, slate bottom, DIY fake rocks for ~50 bucks.
Stuff's expensive, but it doesn't HAVE to be as expensive as most people are saying.. I don't know how you spend 20 dollars on greens. My dragon could have the most varied diet in the world and there's no way in hell he'd eat even 5 bucks in veggies a week. I spend around 6 or 7 and throw away more than half when they start looking bad. Not to mention, there will only be a very short time where he is eating a LOT of veggies AND a LOT of crickets if he does at all.. They start off eating mostly crickets and move to eating mostly veggies.
Vets can be expensive, but I just got a fecal/exam/prescription for pinworms for under 75 dollars.
My lights and heat cost around $2.50/month
60 a month for freeding one BD? You're already on the internet, you really need to use it to order your bugs, or start a colony...
So ya, it gets expensive, but paying 600 for a BD setup is kinda like paying sticker at the car dealership. If you really research and hunt down some deals you can get a Beardie and a complete set up in the 150 neighborhood, and running costs around 20-30 bucks a month.