After FreedomPop pre-launched its new virtual network to combat against rising wholesale access costs from merging partners Sprint and T-Mobile, Sprint has cut the line with a summer-only promotional plan called Unlimited Kickstart.

Customers either bring their own compatible device (perhaps from MVNO using Sprint’s network) or buy a new phone from the network, port their number over and get unlimited talk, text and data for $15 per month with AutoPay. While there’s no contract to sign, keep in mind that you may sign an equipment installment plan if you’re buying a phone from Sprint. Also, data speeds are limited to 480p resolution for video, 500kbps for music and 2Mbps for streaming.

The deal pre-empts a $15 per month plan from FreedomPop’s UNREAL Mobile. Details of that plan have yet to be revealed and a closed beta program is told to launch early this summer.

Meanwhile, this plan launches June 8 (tomorrow) and lasts for a limited time.