In the battle for the best shared family, currently being waged between T-Mobile, Sprint, Verizon, and AT&T, Sprint upped the ante. Late last week, the third place (maybe fourth place) carrier announced a new family plan, featuring 12GB of shared data for only $90 per month.

Interested customers can get up to 10 lines, each with unlimited talk and text, along with 12GB of high-speed data to share. Additionally, Sprint lowered the per-line smartphone access charge from $25 per month to $15 per month, although – and here’s where things get really interesting – it will waive the access charges completely for one full year for anyone who ports their numbers from another carrier.

Data-only devices like tablets and mobile broadband devices can also be added to this plan – tablets normally cost $10 per line and hotspots or other data devices usually cost $20 per line. Additionally, Sprint will still pay the ETFs for (up to $350 per line, with a four lines maximum) for anyone who switches. The only catch? All devices must be purchased through Sprint’s Easy Pay or the Sprint iPhone for Life Plan.

In any case, this is certainly not a bad deal, so it will be interesting to see how T-Mobile responds.

[SprintThanks, Bill!