If you have more time, always start first on the list. If you have an entire day to shop, or more nights at the shop before you need the dress, then start at step four. The first part of the list, the more money you will likely save.
Go to a department store. You can also try a department store such as Target and Wal-Mart. These stores often have cheaper materials, so this step is skippable if you need a very high-end piece. However, many cocktail dresses are worn only once or twice, and some clothing in these stores will be up to hundreds of wearings. This is the first step that will (almost 100%) to ensure a dress in your size, although, again, you can not find the best selection. Navigation thing will have much less time, however, as they have a limited number of styles, instead of a style for each piece.
Go to a department store upper end. Discover a store like Nordstrom Rack or Fred Meyer for your dress. These stores generally offer a higher quality (and higher cost) piece of the above stores. The shopping experience is the same as it is in the low-end department stores, though often the design is not so varied. If you fit into a dress size 4-12, then you'll probably be lucky for them, but outside this range tend to have less available. You can find a cocktail dress for $ 25-50 in a department store high