Ummm, paging Venmo.

Facebook is eating the cost of P2P transactions so it can own social payments like it already owns advertising and chatting.

That’s the word from industry insiders mulling over Facebook’s announcement today that users can send money to friends for free using their Visa or MasterCard debit cards in the company’s Messenger app. Facebook has been telegraphing this move since hiring PayPal President David Marcus to run Messenger back in June 2014.

The social network, with 1.2 billion users, has always been the elephant in the room with social payments, or maybe the 800-pound gorilla. PayPal-owned Venmo currently rules the P2P space among millennials, but Facebook, with its free service, will likely eat into its volume. Venmo is also free for most debit cards and bank account-linked transactions.

Running on the debit network rather than credit cards gives Facebook a lower wholesale cost to begin with and the company likely received highly advantageous deals from the networks.

Facebook has “struck a deal with the debit card networks. And it is one heck of a deal for both parties,” said a payments expert who saw a pre-release version of the service. Why would the networks offer a deal to Facebook, and why would Facebook offer the service for free to its users?

Because the deal will deliver volume to the networks and put Facebook in the center of frequent customer transactions.

Facebook has done payments for a while, but revenue has been flat and limited to gaming purchases and the like. This changes the game for Facebook, to say the least.

The service allows users to load cards using their smartphone cameras and authenticate on iPhones using TouchID, according to one expert. Both features are reminiscent of Apple Pay.

Facebook is reportedly the home of older users these days, with youngsters fleeing for Instagram (owned by Facebook) and Venmo and the like. P2P is also more commonly used for high-value transactions such as rent payments rather than splitting dinner or movie tickets, but fun, quick, casual transactions are still thought of as the classic use cases.

“Network effects will kick in and start excluding players,” tweeted James Wester, research director for global payments at IDC.

Facebook’s real advantage? It’s “always on.”