After you upgraded to iOS 7 and supposedly you have the iPhone 4s or newer, you will have a new micro-location based technology called iBeacon. The technology uses a component dubbed as Bluetooth Low Energy as part of Bluetooth 4.0 specifications.
App developers and beacon maker can create an indoor location aware application based on this technology. A Polish company called Estimote, based in Silicon Valley, just announced pricing for its iBeacons. $99 can give you 3 units that can be placed at the desired locations. Roximity is another start-up company that leases beacons for monthly fees.
The battery powered beacons (the battery life is about 2 years) can detect supporting smartphones when they get within 30 ft radius of proximity to trigger corresponding app to broadcast information such discounts, detailed info about the products that are in sight, etc.. The API can issue both enter and exit triggers for appropriate actions. One of the benefits of BLE is the coverage and the cost of the chip that is much cheaper than NFC, which has been endorsed by Google but lately the company also jumped on BLE bandwagon.
PayPal recently, issued a similar technology for friction-less mobile payment. Apple could also combine iBeacon and PassBook app for similar mobile payment. We should expect to hear more about this promising technology in the months to come.