Got an old Sprint phone? FreedomPop will activate it under its freemium plans

FreedomPop just made its freemium phone service much more attractive to customers who happen to have an out-of-contract Sprint(s s) phone lying around. With Sprint’s blessing, the mobile virtual network operator has implemented a bring-your-own-device program that allows customers to activate several older model Sprint WiMAX phones and even the LTE-powered Samsung Galaxy S III under a FreedomPop plan.

FreedomPop launched its VoIP and IP-messaging service in beta last month, giving the first 10,000 customers willing to buy its $99 tweaked HTC Evo Design the option of a free 200-minute, 500-message and 500MB monthly plan. According to FreedomPop co-founder and CEO Stephen Stokols, it maxed out beta enrollment in 24 hours and has since logged a waiting list of 200,000 people.

Many smartphonesStarting Tuesday, FreedomPop is expanding its beta to at least another 10,000 subscribers with a different HTC phone, the EVO 4G (also $99) as well as taking in customers who port over Sprint devices.

The reason the devices have to be from Sprint is because FreedomPop uses Sprint’s network. As an MVNO, FreedomPop is an infrastructure-less carrier buying wholesale data from network operators. Most MVNOs typically buy voice minutes as well, but FreedomPop is one of two mobile service providers in the U.S. (the other is TextNow) that has managed to throw off the 2G voice and SMS yoke completely. It’s a pure IP carrier, saving it considerable costs.

You won’t be able to bring any Sprint phone over to FreedomPop, at least not yet. The device can’t be under contract with Sprint, and FreedomPop is gradually adding support for the 500 or so phones that currently run on its network. It’s starting with about 10 of the most popular devices that are either already or soon will be free of Sprint contracts, including the HTC Evo 3D and Evo 4G, the Samsung Galaxy S III, Epic 4G and Epic 4G Touch and the LG Optimus S.

Stokols said no iPhone is on the list for two reasons: one, FreedomPop is still trying to optimize its VoIP and SMS client to work in Apple’s closed OS; and two,  Sprint has a distribution deal with Apple(s aapl) that prevents it from activating iPhones with a partner (though fellow Sprint MVNO Ting has been activating iPhones quietly in a beta program).

The goal, however, is to bring the iPhone into the FreedomPop fold as well as any Sprint-supported Android(s goog) device. In case you’re wondering, that means you’ll be able to bring a new Google Nexus 5 to a FreedomPop plan, and you won’t have to buy one from Sprint and wait around to complete your contract. FreedomPop will soon support activations of unlocked phones that work on Sprint’s network so a Nexus bought on Google Play will work with its service, Stokols said.

Nexus 5

Stokols also said that the Sprint-device limitation may also be dropped as it explores the option of signing an MVNO deal with an additional carrier. If it were to buy data from AT&T(s t) or T-Mobile(s tmus), it wouldn’t have to mess around with porting. It could just distribute SIM cards that customers could insert into any unlocked GSM phone. There’s certainly precedence for this. The country’s biggest MVNO, TracFone(s amx) buys airtime from all four the country’s nationwide operators.

“We’re doing enough volume now that we could support multiple carriers,” Stokols said. In August, FreedomPop reported 100,000 mobile broadband modem customers, a little over half of which subscribed to one of its free plans. That certainly doesn’t make it as big as TracFone (which has more than 22 million customers), but once its smartphone service comes out of beta, it has the potential to grow a lot bigger.

FreedomPop will be activating eligible Sprint phones from its website. Customers will also have download its app and dialer software so all calls and text messages are routed over its IP service.

Smartphones image courtesy of Shutterstock user Reno Martin