Dont know but there was an advert in H&H this week warning people about buying imported ones. It gave some phone nos. to contact where they can give advice. If you dont have H&H PM me and I will try to find phone no. if you want it.
I was looking at buying a donkey a couple of years ago (not a miniature) and the cheapest I found was £300 and he had major problems. Young, unbroken and terrified of people...
I'm not sure about where you are but over here (Canada) the prices range a great deal. Our was purchased for about £75 but I have seen them for as much as £500 (hope my conversions are right). I would recommend one though, mine is great I love her! The horses weren't sure at first but they quickly got used to her and now they all love her.