Instructions
Explore Disney Store's merchandise. If you don't have a Disney store in your city, visit its website and enter into the search engine, "Cinderella costume." Your search will reveal that the proper name of the product is "Glitter Cinderella Costume for Girls" The listing will indicate a sale price, if applicable, but as of 2010 the original price is $39.50. The store's Halloween 2010 promotion marks down the dress's price by 25 percent.
Use your favorite online auction site's price estimation tool. For example, go to eBay, click on the "Sell" button on the top navigational bar. Find the "what's it worth" tool and enter a description of the item into the field, for this example "Cinderella costume." In this case, the average selling price is $23.58 as of 2010. But this number is calculated from Cinderella dresses of all types and conditions. Search individual entries for a clearer picture.
Comparison shop online. Plenty of websites compare various prices, but the best way is to simply enter "Disney Cinderella costume" into your favorite search engine to see how all retailers price this item, including online stores and brick-and-mortar retail centers. In this example, a Google search for "Disney Cinderella costume" yields several prices, ranging from $24.61 to $34.99 as of 2010. However, this search also pulled up different Cinderella dresses, so make sure you are comparing apples to apples by honing in on the identical dress.