i want to start one but i want some dar frogs in in and are they expesive to to keep them
These guys are great. They are very good at informing their customer. http://www.blackjungle.com/
I don't have frogs, but I have bought plants from these guys.
From what I know, the frogs are easy to maintain after you have made the investment of buying a good terrarium, doing researching to educate yourself so you can set up and maintain good habitat.
Here is a link that might be useful: blak jungle terrarium supply
Theyre on the higher price side, but I have seen places where they have sold them for $25-30.