Image: Man Taking Money Out of Wallet © NULL,Corbis

Attention shoppers: There's a battle shaping up for your wallet in 2013.

This time, it's not about the wallet in your pocket or purse. The battle is for your mobile wallet.

Don't have one yet? By the end of the year, you probably will. In fact, you may have several, as you do credit cards. Multiple mobile wallet providers will be trying hard to get you to use theirs.

By mobile wallets, I mean apps that let consumers use their smartphones or tablet computers to pay for stuff in stores, typically using a credit-card or bank account as a funding source. They're a boon for marketers who want to sell you stuff, and they could be a boon for you -- since retailers will try to lure you in with deals on things they know you want.

But it may seem a little creepy, too, as if a stranger were looking through your real-world wallet. Your mobile wallet will know a lot about your spending habits, and that knowledge is a valuable asset that can be sold to retailers.

Here's how this battle for your new wallet is shaping up.

Finally ready to roll out

The idea of waving a device and paying for things is hardly new. But now, the technology and the incentives to make it happen have advanced far enough that big chains like Wal-Mart Stores (WMT), brash startups, phone companies and credit-card companies will soon be fighting hard to get your mobile-wallet business.

"I think 2013 is going to be the year where mobile payments will happen and there will be a winner, or mobile payments won't ever happen at all," says Seth Priebatsch, , the CEO at LevelUp, a Boston startup with an innovative and potentially game-changing mobile wallet offering.

For consumers, this bears watching because it will change how you spend, and it will be used to try to make you spend more. For investors, this is a battle worth studying because there will major winners and losers.

I'll get to the investment plays in a second. But first, what's this mobile wallet battle really about?

The marketing angle

Let's be clear: This isn't about retailers wanting to give you the cool experience of waving your smartphone to pay for stuff. True, it could be cool -- and convenient. Studies show that smartphones shave 17 seconds off a transaction, says James Anderson, the senior vice president of mobile payments at MasterCard (MA).

But really, this battle boils down to two big goals for mobile-wallet providers and retailers.

Goal No. 1: Make mobile devices a better marketing platform.

Truth is, you may be thinking credit cards and debit cards are convenient enough; why replace them with phones? But you're not thinking of it from the marketer's angle. Retailers, credit card companies and new arrivals to payments like Google (GOOG) and LevelUp want to turn your smartphone or tablet into a better sales platform.

Credit and debit cards don't have display screens, and you don't hold them in your hand while walking down a store aisle or through a parking lot. Phones are close at hand at these times -- prime moments to present deals to shoppers.

Mobile wallet apps also let the issuers gather incredibly specific data about every item you purchase, down to stock-keeping unit or "SKU level" data. The idea is that, armed with this data, your mobile wallet will let sellers target you with the deal most likely to make you spend, at the moment you're ready to spend.

This can sound Big Brother-ish, which is why mobile-wallet providers will likely tread carefully. With LevelUp's mobile wallet, for example, these offers mostly appear when you open its app. That's better than the unsolicited texts or emails that most of us find annoying. (LevelUp also sends out some email offers.)

There can be real pluses to this for consumers. In the early days, like 2013, competitors will be fighting to offer you sweet deals to get you onto their systems. "It will be a bloodbath in 2013," predicts Aaron McPherson, an analyst who follows the mobile-wallet business for IDC, a tech research firm. "A lot of well-financed competitors will be doing whatever they can to get consumers and merchants to adopt their wallets."

Longer term, consumers benefit because moving marketing to their smartphoneswill help retailers push highly targeted deals. You might get a great discount for coming in on a rainy day, or deals on inventory that's piling up that day.

You'll get discounts on stuff you want to buy anyway. And if the privacy angle bothers you, you opt out.

Goal No. 2: Take back the credit card fees.

Retailers resent the roughly 2% of every transaction they have to give up to the credit card companies and banks behind the cards. Retailers notice that card issuers use a lot of that money to fund loyalty programs. Retailers would like to take some, or all, of that money back, to fund their own loyalty programs.

Mobile wallets may eventually lead to new payments systems that help them do this, or at least give them leverage to negotiate down fees. "Retailers pay the fees, but the fees benefit the banks, and this drives retailers crazy," says Jason Benowitz, co-manager of the Roosevelt Multi-Cap Fund (BULLX). "The mobile wallet gives retailers a chance to take this money back."

Of course, it's not clear that's how it will play out. But the possibility of grabbing some or all of the credit card fee is one of the powerful forces driving retailers and others to promote mobile wallets.

The key players

Here are some of the top combatants in this battle, and some of the potential winners and losers for investors.

Google: Google's first shot at the mobile wallet didn't pan out, but don't let that fool you. Targeted marketing based on intelligence about consumers is Google's specialty. And Google has a lot of cash to fund its entry into mobile wallets. "They're the 800-pound gorilla," says McPherson.

Google's potential in mobile wallets is just one more reason to own this stock, which looks cheap right now in the low $700 range. The stock is held back by investor worries about the shift in search and display advertising to mobile, where Google's rates are lower. But that will change as more advertisers move to the mobile platform and bid up the value of ads. A Google mobile wallet is part of this move, and it could ease some of the doubts holding the stock back.

eBay (EBAY): This company's PayPal division has big potential as a mobile-wallet provider since it already has 114 million active user accounts, says Benowitz, of the Roosevelt Multi-Cap Fund. Plus, eBay istrusted among merchants. So far it hasn't rolled out a real mobile-wallet product, but it will. PayPal is already a solid source of growth for eBay, and it’s one of the reasons the company has an attractive moat, something investors look for. A mobile wallet will only make PayPal more valuable to eBay.