The biggest difference between a consignment shop and a thrift shop is the quality of the merchandise. The second are the prices. Consignment stores hand pick items they will sale. Thrift shops accept donated items, so they are not as discerning. Merchandise sold at consignment shops is gently used or new. Consignors receive a percentage once the item has been sold, which is why their prices are higher. Thrift stores will provide people who donate a tax deductible receipt, as most of them benefit a cause or community program.
A consignment shop accepts merchandise on a consignment basis, paying the owners of the merchandise a percentage when and if the items are sold. The majority of such shops pay the owners from 40 to 60% of the selling price, and have a policy of displaying goods for anywhere from 30 to 90 days, although there is a wide range of policies across the country. Some consignment shops also purchase a variety of items outright from individual owners and/or wholesalers.
A thrift shop is run by a Not For Profit organization to raise money to fund their charitable causes. These range from the large Salvation Army / Goodwill chains to individual school, church or hospital thrift shops. Not For Profits can obtain goods through donations or they could operate on a consignment basis—some do both.
A resale shop is the phrase most often used for stores that buy their merchandise outright from individual owners, like a vintage store. A consignment or thrift shop can also be called a resale shop, but ONLY a store that actually consigns their inventory can be called a consignment store, and ONLY a store run by a Not For Profit organization is considered a thrift.
From the blogpost, Difference Between Consignment & Thrift Stores, October 2, 2011.