The plan can only be deliberate, egregious price discrimination. I found out about it because T-Mobile was heavily advertising it on their website. So I tried to sign up. You can't do that; you have to either order a SIM card from them (which is free), or get one from Walmart. I tried to get a SIM card from the local T-Mobile store. They don't sell those. I ordered a SIM card online and had to wait a week. When it arrived, I activated it on (surprise!) the T-Mobile website. I guess you can do that after all.
Note that in ordering the SIM card I did not indicate that I wanted any particular plan. The $30 plan just "happened" to be available for that card.
Was I willing to wait for one week in order to lower the bill for a large recurring cost by 40%? Yes. But T-Mobile seems to be gambling that most people aren't.
Actually SIMs aren't free, they're normally $10. You can sometimes find them for $1 if you look around hard enough [1].
I've been using this plan for about a month or so and coverage has indeed been a little spotty in my area but it's good enough for my needs. If you do want to try it out here's a tip port your number: do NOT do select the option to port during the online activation process. Sign up and activate your SIM FIRST and then call in to initiate a number port request. Once you've activated and signed up for the $30 plan with a port request, there's no way to get a temporary number while waiting for the port request to complete.
I consider $10 with a $10 discount (applied before payment) "free". I ordered straight through T-Mobile's web site. Yes, I may have actually paid some amount under a dollar, and no, I didn't pay more than a dollar. I'm still willing to call it "free".
Note that in ordering the SIM card I did not indicate that I wanted any particular plan. The $30 plan just "happened" to be available for that card.
Was I willing to wait for one week in order to lower the bill for a large recurring cost by 40%? Yes. But T-Mobile seems to be gambling that most people aren't.