Now that Apple Pay is here, you'll soon be hearing more about Google Wallet.

Apple has garnered a great deal of attention this week for introducing Apple Pay, but Google Wallet, another NFC-based solution, has on the market for three years. Google is planning a "couple of ad campaigns" in the fourth quarter for its mobile payment system, according to Sherice Torres, Google's director of marketing for commerce. It's still unclear whether the plan will include TV.

Google has advertised Wallet previously; an inaugural ad from 2011 featured Seinfeld's George Costanza and his overstuffed wallet. (That ad has since been removed.)

Google hasn't released any stats on usage except that it has grown 20-fold since 2011; regardless, Apple Pay quickly overshadowed it. "That's the plus and minus of being an innovator," Torres said.

"We got into mobile payments because one of Google’s main goals was to expand the use of Wallet to replace cash," she added. "Anything that that encourages people to try to use their phones is good."

When Wallet was released, you couldn't use it in many places; most Android handsets didn't even offer it. That's no longer the case. Tap and Pay via Wallet is now available on almost all NFC-enabled devices with Android 4.4 (KitKat) or higher. Like Apple Pay, Wallet can be used at about 220,000 merchants that have NFC readers, which is about 10% of all merchants in the U.S.

Greater availability has not translated into increased visibility, though, hence the ad campaign. Torres didn't discuss it in detail, but emphasized that Wallet has been on the market for a long time and was the first provider to provide tap and pay.

Marc Freed-Finnegan, the former Google Wallet product lead and the current CEO of Index, told Mashable that AT&T, Verizon and T-Mobile limited Wallet's availability since they controlled which handsets they offered. The three offer an NFC payment solution called Softcard (formerly known as ISIS).

Apple is Apple, though, and was able to push through its own NFC solution. "Apple has control over its hardware and software while Google really just has control over its software," Freed-Finnegan said. "Apple said to [the carriers] 'Here's our device. Take it or leave it. You can't mess with anything.'"

Google has another pitch to merchants. Apple Pay is working with a limited group of retailers and credit card issuers, but Google Wallet is compatible with any bank and any credit card, according to Torres.

Despite glowing reviews for Apple Pay, Freed-Finnegan said Apple and Google still have a problem marketing the tap and pay system since it's not much easier to use than a credit card.

"NFC is nice, fast and convenient, but what's the real proposition for consumers?" Freed-Finnegan asked.