New ways to buy things with your mobile phone are popping up all over the place, as we’ve been reporting this month. But which technologies will win? At Xconomy’s Mobile Madness conference on Wednesday in Cambridge, Massachusetts, three CEOs in the game prognosticated.

• Seth Priebatsch of location-based gaming startup Scvngr, which recently launched a spin-off called LevelUp (which combines location-based gaming with deals offered by sites like Groupon), said consumers would make the call. “The consumer controls pretty much everything. While everyone [merchants and credit-card companies] has a lot of blocking power—and everybody needs to cooperate—it will be consumer choice that drives adoption of whatever platform ends up winning.”

• Chris Gardner of Paydiant, which lets banks and retailers run their own mobile wallet and loyalty platforms, said merchants would be in the driver’s seat: “History is the judge: All payment models have started with merchant acceptance. Until retailers give you a place to use your mobile money, there is no ‘there’ there … Ultimately, there will be a few winners. Not one, but a few.” And he and others pointed out that what will make merchants care is if mobile technologies prove better at roping in customers with loyalty programs, coupons, and other incentives.

• Andrew Paradise of Aislebuyer, which provides mobile checkout technologies, made the point that the plethora of technologies and strategies was a good thing—it echoes the existing chaos in our wallets (credit cards, debit cards, cash, gift certificates, and store cards—often with special incentives attached). The diversity of approaches will gradually show people how to do similar things with phones. “It’s going to take a variety of technologies to drive the idea of mobile payments in stores,” he said.

Consensus point: diversity is good. Google has been pushing its “Google Wallet,” in which special chips called near-field communications wirelessly transmit payments with the wave of a phone; and three carriers are pushing a similar strategy. Certain apps give you a QR code that is then scanned, and you get a digital receipt.  Merchants including Starbucks, Target, and Walmart are developing their own systems. Square lets merchants swipe traditional cards with a card-reading gadget that plugs into smart phones. Apple, the secretive behemoth, might someday unveil a strategy.

But nobody has a corner on mobile wallet. The phone itself is the wallet. That’s the point: it will eventually fill up with chip-and-software versions of the same stuff our wallets are crammed with today.