While many view Walmart as simply a retailer, millions of Americans rely on the company as their main source for financial products. Walmart offers a variety of debit and credit card options, as well as services such as money transfers, remittances, check cashing, tax preparation, and billpay. So it’s no surprise to see that PayPal has joined forces with the retailer today to fortify services for their joint customers.

As part of the partnership, PayPal users will be able to withdraw and deposit cash into their PayPal account at one of Walmart’s 5,000 brick-and-mortar stores. In addition, PayPal Cash Mastercard customers can access their cash balance using Walmart service desks, ATMs, and cash registers. This is the first time PayPal users have had the flexibility to transact in cash, but it comes at a cost. Each cash transaction is priced at a flat, $3 service fee. The parties have not disclosed how that fee is divided between Walmart and PayPal.

In a press release, Dan Schulman, President and CEO of PayPal said, “We consider this a key collaboration for both PayPal and Walmart. We are committed to working together to make it simple and easy for people to use PayPal cash in and cash out money services at every Walmart location in the U.S. We look forward to working hand-in-hand to help people and families with their financial services needs.”

PayPal’s mobile app offers many of the same features as a traditional banking app, including PFM and money management tools, peer-to-peer money transfer options, and investment opportunities via its partnership with Acorns. Qualifying borrowers also have access to a line of credit. Today’s partnership with Walmart is likely a move to stave off the threat from Amazon, which has been rumored to further its lineup of alternative banking options via partnerships with traditional U.S. banks.

Tying cash into PayPal’s existing robust mobile infrastructure is a key way to target the underbanked population. Now that Walmart is serving as PayPal’s brick-and-mortar “branch,” what’s next for the payments company– mortgages?

Starting today, PayPal users are able to deposit cash at Walmart. The cash out feature will be available at all U.S. Walmart locations next month. Founded in 1998, the alternative banking provider showcased its Instant Account Creation feature at FinovateFall 2012. PayPal’s market cap sits at $90 billion.