Information about Bearded Dragons?

Hello, im just asking to the people that own or have owned a Bearded Dragon from baby to adult how much they spent on all the items and cages that they get. I'm thinking of buying a Bearded Dragon,but first i wanna buy the cage,food,cage decorations etc. then getting the bearded dragon.And just wondering again...do bearded dragons eat watermelon? because i use to have an iguana and my iguana ate watermelon im just wondering what the deal is there.