Rhapsody - Thank you,Thank you,THANK YOU for not just recommending a good enclosure but the warning about sand.
Tile can be used as well (newspaper is cheap& you just toss it after),with tile it might be a good idea to silicone it in the enclosure (with safe sealant) that way nothing gets stuck between aquarium& tile.& You just wipe it down =]
About the size/ age of the dragon,i'm not exactly sure.
I wouldn't go by what pet stores say...ever.
(With my experience with pet stores.)
Sand can cause impaction.
Not even my adult leopard geckos get loose substrate.
They are on newspaper& soon will be tile.
You could also look into reptile carpet (you'd have to wash it quite frequently though so I'd buy more than one).
I'd give a BBD other things to "go under".
Like those neat log things.
My geckos love them =P.
Is the BBD eating pinhead crickets?
Everyone I talked to with BBD said as a baby they just eat pinheads.
I'll try to get more info for you ASAP