You probably won't enjoy them as much as you might think. Not just because of difficulties caring for them, but because you would never see them. They remain burrowed deep down in the sandy soil in Aestivation for extremely long periods of time. Most of the year as a matter of fact and only surface (as their name suggests) when heavy rain returns. Then they emerge, shed, feed, breed, and then burrow back down.

Chances are that you would never see them which makes caring for them difficult. They are very small too. I have no experience with this species or other similar species, but I'm also not trying to discourage you from getting some rain frogs. Just offering some precautionary info. If you could find a way to keep them successfully I would love to see pictures and updates. They are very pretty and yes "cute", but know what you may be getting prior to attempting to aquire some.

Alex is right. The two species he mentioned are occationally available, but I've not heard of Breviceps namaquensis being available.

Good luck!