Now you can -- up to a point -- thanks to a new feature launched this week at a site called Lyst.
Lyst, a London-based startup, is a little like Pinterest. The site invites you to follow designers, stores, bloggers and your friends, from which it creates a feed of clothing and accessories you can add to your own "lyst."
If an item on your lyst is discounted, you'll be notified by email.
Now, if you connect your Pinterest account, you'll receive an email notification when an item you've pinned on Pinterest goes on sale, too, so long as that item is also indexed on Lyst.
Lyst's index is limited largely to fashion brands and retailers -- so if you mostly pin books or furniture, this tool isn't going to be terribly useful to you.
To see which of your pins are recognized by Lyst, check out your "Collections" under "My Lyst."
A bonus: If an item you've pinned from one retailer (say, Neiman Marcus) goes on sale somewhere else (at Nordstrom, or Endless), you'll still get notified.
Lyst also offers a Runway Tracking tool that lets you know when your favorite runway looks arrive in stores. The tool was launched during New York Fashion Week last September.