The catch is that the winner of the mooted auction would be required to filter adult content from the free service. Over 18s will be able to lift the filter.
The remainder of the licensed spectrum would be used to provide faster paid Internet connections and other services.
The proposed spectrum - known as AWS-3 - is currently unused.
As you might expect, opposition is coming from mobile phone companies. The idea of someone giving away what they currently sell must be particularly challenging.
Some of those objections are being cloaked in assertions that a free service would somehow interfere with existing operations (as if it would make any difference if those same radio waves came with a price tag), but the FCC has determined there is no significant risk of harmful interference if AWS-3 is put to use.
Other complaints are coming from libertarians concerned by the idea of a filtered Internet.
What will the FCC require in terms of filtering or censorship? See page 2.
The FCC's proposal says there must be a network-based mechanism "That filters or blocks images and text that constitute obscenity or pornography and, in context, as measured by contemporary community standards and existing law, any images or text that otherwise would be harmful to teens and adolescents. For purposes of this rule, teens and adolescents are children 5 through 17 years of age".
And if your paid wireless service on this spectrum comes with a download quota, don't expect to switch to the free service when you hit the limit for the month: "If a broadband user pays any compensation for any broadband service directly or indirectly affiliated with the licensee, the user does not receive free service."
So keep your fingers crossed that if there is a quota, the successful bidder will cap speeds to match the free service rather than imposing excess data charges.
The FCC proposal appears to be related to - or at least bears similarity with - one floated by M2Z Networks to provide "free, fast, and family-friendly wireless broadband Internet connectivity to at least 95 percent of the US population."
M2Z has previously said it would provide 384/128 Kbps service ("competitive with low-end DSL") for free, funded by revenue from location-sensitive advertising. The paid service would run at 3 Mbps.
The FCC proposal requires data rates of at least 768 Kbps downstream for the free service.
Rather than paying upfront for a licence for the required spectrum, M2Z wants to pay the government an ongoing fee based on subscription revenues.
The company is led by Milo Medin, who was co-founder of cable Internet provider @Home. Its backers are some big names from the venture capital industry: Kleiner Perkins Caufield and Byers, Charles River Ventures, and Redpoint Ventures.