A lot. A painful lot. The original expenses are ok, but babies can cost $100s per month for food, electricity, etc. Plus, you have to count in vet bills, heat bulb replacements, and continually larger cages for growing beardies.
-The enclosure itself is one of the most expensive things to buy. Babies can be housed in 20-ish gallon tanks, juvies in 40-ish gallon tanks, but adults need a minimum of a 4x2x2' enclosure, which can get really expensive. Instead of a glass tank, I reccommend investing in a wood, melamine, acryllic, or other type of custom cage. These too can be expensive. I built my own for under $50, but it took 4 full days of me and a friend working hard to get it done.
-Dragons are fairly cheap. Babies at pet stores (which overprice them to an extreme) are around $60. Babies at expos can go for $10. A good price for an adult is $100.
-Lighting/Heating: ReptiSun 10.0 (or MVB) is required for UV. Other than that, you just need heat and light, which can be provided in a combination of halogen bulbs, household bulbs, red bulbs, or ceramic heat emitters. Plus fixtures for all of the above.
-Most cage decor you can get for free; cardboard boxes, rocks, logs, etc. You will need a digital thermometer with a probe ($12) and a substrate. My favorite substrate is tile.
-Food, food, food, food, and food. Did I mention food? This is by far the most expensive part of owning a dragon. Especially a baby. They eat like there is no tomorrow. I'm spending about $40 per month on crickets for my adult beardie, plus all his greens and veggies, plus mealworms. And he's an adult. Babies eat so much more. So, you need to make sure you have a continous flow of cash. If your parents won't pay for the food, you will need to get a job babysitting or something like that. Make sure you will be able to afford food for years to come.
Good luck! Beardies are the most amazing things you could ever imagine. Believe it or not, every single penny of the hundreds of dollars you will spend on yours is all worth it a hundred times over.
Things to remember:
-DO YOUR RESEARCH!!!! And ask us any questions you have. This is an awesome site with very friendly people that are also very helpful.
-Never buy a beardie from a chain pet store (PetCo, PetSmart, etc). The storekeepers rarely know how to care for reptiles. And don't think you'll be doing a rescue. If you "save" a beardie from them, they will just buy another. I boycott those stores altogether because of how they treat their reptiles.
-Keep us posted. If you do get a beardie, we want pictures!!
Again, I wish you the best of luck!!