Of all concepts unique to the USA, the consignment store is probably the one I value the most. (Sorry, high-fructose corn syrup...I will never understand you.) I've bought and sold, both online and offline, from these genius little establishments for years. For shoppers, their ranges are far more reliable than eBay, and as a seller, it's a chance to get rid of nice clothes that eBay's auction freaks just won't appreciate. But what I love even more than the financial benefits are the ethical ones. The idea of giving people access to brand new clothing with zero toll on the environment just makes sense. What's more, by buying consignment, you can be sure you're not producing demand for questionable labour practices in shonky factories.
The first store that hooked me back in 2010 was a little chain called Plato's Closet. What differentiates it from an op shop is its buying policy: it only buys clothes that are no more than 18 months old, which makes its range fairly reliable as far as styles and condition. (Technically, it's not a consignment store, since it buys and sells rather than selling for you and taking a cut off the top. But to a shopper, it's all the same.)
My love for consignment came full circle when Plato's Closet asked me to shop their Littleton store and see what I could style up with a $50 gift card. This (brand new!) J Crew skirt was $10 and the Gap shirt was $6 - I'm not complaining.