Gift cards are big business — so big, there are entire marketplaces for them, it turns out.

Raise, one of the largest, is announcing today that it has raised $56 million to help it grow and expand.

Through Raise, shoppers can purchase discounted gift cards to use online or in stores, and sell unwanted gift cards at whatever price they choose in exchange for cash (it recommends they discount them by at least 5 percent). Raise makes digital cards available online immediately, ships physical ones to buyers for a tiny fee, and makes many of them printable so they can get them right away. It takes a 15 percent cut from each sale.

Raise launched an iOS app in November (Android is coming soon) that lets shoppers purchase cards and instantly redeem them online or at a physical store by scanning a barcode with their phone.

Raise isn’t alone in providing a place for buying and selling gift cards. CardPool and CardCash, among others, also let people buy discounted cards and sell unwanted ones for cash.

New Enterprise Associates (NEA) led the round, with additional participation from Bessemer Venture Partners (BVP), the Pritzker Organization, Listen Ventures, and other existing investors.

Raise was founded in 2013 by George Bousis, and is based in Chicago. It has raised $81 million in funding to date.