My advice, save save save money! Your gonna need a lot of things for a bearded dragon, and even if you calculate a amount, save more. Just do it. Your gonna be glad you did, and even if you end up staying within budget, hey thats awesome, but when I bought a bearded dragon, there was PLENTY extra costs
Depends on the gecko, but in general, beardies LOVE attention from their owners, and thrive on interaction with them. They require a bit more work than say, a crested gecko or a leo; they require a lot more space, temperature requirements are higher, they eat more - both bugs and fruits/veggies, and I believe they need correct UVB lighting as well. But man, if I had the space and setup for one, I would really consider it. They make great pets!