Sprint dropped its $32 billion bid to purchase T-Mobile earlier this month because US antitrust regulators had indicated that they would block the merger. Now, it looks like the government got it right for a change: In just the few weeks since that reversal, both Sprint and T-Mobile have moved aggressively to lower prices and make more versatile wireless plans available to customers.

T-Mobile got started early—indeed, before the merger was even officially canceled—when it announced a plan for a family of four which includes unlimited text, talk and shared data, 10 GB of it LTE data (2.5 GB per line), for just $100 a month. The plan undercut similar offerings from AT&T, Verizon and Sprint by a full $60 per month, and of course T-Mobile also offers unlimited international data and text in over 120 different countries as part of the package.

This week, however, Sprint responded: It is now offering a promotion through 2015 that provides up to 10 lines, 20 GB of shared data, and unlimited text and talk ... for just $100 a month. After the promotion is over, this plan will cost $160 per month, or customers can switch to a four-line plan with the same features for $100 per month.

"Sprint is offering the best value to data-hungry consumers. Period," Sprint CEO Marcelo Claure is credited with saying in a prepared statement. "We are doubling the high-speed wireless data because today's customers rely so much on their smartphones and tablets. We are so certain that this is the best value on wireless today that for any customer who wants to switch to our new Sprint Family Share Pack, we will reimburse them for the cost to end their contract with another carrier."

Sprint is the third-largest wireless carrier in the US, and T-Mobile is fourth. The two firms had intended to take on AT&T and Verizon via a $32 billion merger that would have been announced sometime this summer. But after regulators from the US Department of Justice and the Federal Communications Commission threatened to sue to block the merger, Sprint backed down, scuttled the deal, and fired its CEO, replacing him with Mr. Claure.

If history is any guide, AT&T and Verizon will move to meet the recent changes by their smaller but more aggressive competitors. Seperately, Verizon recently announced a $60 monthly plan for individuals that provides unlimited talk and text and 2 GB of data. That's a $30 savings over the original scheme, and it slightly undercuts a $65-per-month AT&T plan that also requires users to bring their own phones. Sprint and T-Mobile offer comparable individual plans in the $50 to $55 range.

This is coincidentally timely for me as I'm going to be reevaluating my own phone plans when I get back from Barcelona: Despite having an AT&T account since 2007 and paying for three lines (with just 4 GB of data) for $160 per month, the carrier refused to unlock one of my phones during this trip. Let's just say I'm seriously considering any carrier that would pay termination fees, and it looks like both Sprint and T-Mobile have relevant offers.