Magnus - Shazam for art
RetailMenot - The RetailMeNot mobile app allows you to find deals on the go for both online shopping and in store shopping.
Masterworks - Invest in the world’s most valuable paintings.
Slickdeals.net - Slickdeals: The Best Deals, Coupons & Discounts on everything
Artsy - A global platform for discovering and collecting art.
Honey - Honey is a browser extension that automatically finds and applies coupon codes at checkout with a single click.