I'm always worried that someone at T-Mobile will notice that plan, say "whoa, how did that get there?", and delete it. It's just so much cheaper than everything else on the market.
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.