My girls have done this several times. Usually they save save save their money because they are about $145 for the basic doll and go up with a Disney outfit but sometimes their softy dad just pays.
I don't think it's worth it to just purchase the outfits as they start at $65 and that is for the basic ones - Disney princess outfits are much higher - I think about $85 to $90. The most fun is making the dolls, anyway. The girls get a big thrill out of doing this & they do it almost every trip.

I love watching it, too. The dolls are beautiful, much, much better quality than AG. They can wear the same clothes, but the shoes will not be interchangeable. The German dolls have wider, shorter feet.
Around the holidays - we have seen this on several Thanksgiving visits - Helmut Engel is in the shop to sign the dolls. He also makes about 30 limited ed holiday dolls. Last years was St. Lucia. My girls have always opted to make their own, but he still signed them. I have seen him in the shop at other times of the year also, but not sure when.
To ship them home, which we have never done as the girls always want the dolls with them, costs about equal to paying the tax and keeping the dolls with you - which you do not pay if you ship them. Our last visit my younger DD made a beautiful doll in a Greek wedding dress - the outfits from the different countries are amazing. Have fun!
Lives4Disney