I got a few adults. One thing you must remember is that when buying an adult, there is most likely a reason it's for sale. Some irresponsible folks will get gravid imports, let them lay eggs, then sell them as breeding size females. Fresh imports many times will refuse to breed for you for a season or two, thus negating the reason behind buying an adult female in the first place.
Even buying a CB adult will not always help, as not every female will make a good breeder. It might be that each time it's been bred it did not take, or threw only slugs. A problem breeder isn't apparent in the snake, and until you bred it yourself a couple seasons, you won't know you've been duped into thinking it was a great bargain.
Getting your own small ones and raising them is a great thing. But you might luck onto a adult breeding size female that is a CB and is not a problem. Just don't count on it as a matter of course, especially not if they aren't from someone with a good reputation.
Eventually I will replace my normal females with morph or hets, but most likely I will have plenty of folks I know, that want those normal females, so I doubt I'd have to advertise them.
Adult het males are more common, as people get a visable morph male to replace him with, they then can let go of the het male.
Good luck, and I hope this helped!