The company announced partnerships with 15 retailers yesterday. Stores like Office Depot, Aeropostale, and Toys “R” Us will begin to offer PayPal’s payment option at their registers.
All Things D points out:

That list includes some overlap with Google Wallet, including American Eagle Outfitters, Foot Locker and Jamba Juice. It seems clear that retailers are willing to try multiple strategies to see what works best.

Unlike Google Wallet, ISIS, and others, PayPal’s system doesn’t depend on near field communication (NFC) terminals at the registers. PayPal uses existing credit card readers that we’re all used to. It has been testing the system out in Home Depot stores across the country since the beginning of this year. You can either pay with a PayPal credit card (plastic) or enter your phone number along with a PayPal pin to complete the transaction. PayPal announced that it’s also partnering with a handful of companies that make POS software, which means that even the not-so-big-name stores can get a piece of the new payment action.