I'm a reasonable guy; I don't expect a $12 halloween costume to last for years and be passed down from generation to generation.  Every year I go online and let my daughter pick her Halloween costume.  Last year (Sept'2010) she picked out this cute "Vampire Princess" costume.  Ordering costumes online is always tough on sizing guesstimates so it is helpful to read the user reviews to get a sense of the sizing.  Based on the reviews I bought a size Small for my daughter and it fit very well - her stats were 43 inches tall and she weighed 45 pounds.

The costume is somewhat disposable but once again I revert back to the fact that it cost $12.  She was able to wear it at least 4 times (school parades, halloween, birthday party, etc) and she looked very cute in it.  It's still in our costume box as a "just in case".  Four stars based on price/value.