Where do you live? It is best to get native species. I think one of the best pond turtles is the painted turtles. In the Eastern US, the Eastern painted is native; in the middle of the country, it's the Midland painted; and on the West coast, it's the Western painted. You can rarely find a local store that sells the adults. It's illegal to buy/sell turtles under 4" but many people do anyway. Turtles are less likely to wander if they are smaller. You will need to fence in the pond area to ensure the turtle(s) doesn't leave. Try contacting your local turtle or reptile club to see if they have suggestions for breeders or turtles for sale or up for adoption. There are tons of red-eared sliders that were cast off by previous owners who need ponds to live in.
My page on turtle ponds is at
http://www.fishpondinfo.com/turtles/turpond.htm There are not many places that sell green frogs but I think Tricker's tadpoles are green frogs.
http://www.trickeri.com/store/p-tadpoles/c...scavengers.htmlI've yet to find eggs from my green frogs this year but, when/if I do, I sometimes share them with others in MD.