I purchased a Prestige one through eBay (snow white) and it is gorgeous and well-made--I think I spent about $45. Really, really nice. Like you would expect Snow White to look IRL.
Then, when I started agonizing over letting her wear this expensive thing to a character meal, a few DIS members turned me on to the
Walmart Disney Princess costumes. I went the other day and scored a Cinderella and a Snow White, each $17.88. They also offer
another version at Walmart which was supposed to be an upgrade, for $25, called the deluxe, but here's a newsflash: I compared the $17 Cinderella dress to the $25 one side by side. Guess which one had a few ripped seams and looked like it was ready for the garbage? Surprisingly, the more expensive "deluxe" version that had these cheap looking sequins on the bodice (Cinderella)--I was not impressed and was glad I didn't waste the extra $8.
The $17 versions from Walmart have the crinoline-like underskirts and netting overlay, but at least for the 3yo and up size, the skirt looks a little shorter than ballgown (ankle) which I prefer b/c it won't cause tripping. Also, I compared the Prestige version of Snow White with the Walmart one and...I have to say, there are
some differences but probably NOT enough to justify the price difference of over $25. Especially when I think about what my DD2 is going to do to this costume over time...
Now that I have it, I might save the Prestige one anyway since it's a larger size and she could wear it next year for Halloween. But before investing $50+, you might check out Walmart and consider these. They do not scream "I am nylon and came out of a cardboard princess dress up trunk."
Good luck!