IS the SD under an obligation to honor $7.48 per year?

I just spent more than half an hour looking through all **Ed’**s posts for it and couldn’t find it anywhere.

Here.

Relevant bit:

Looks pretty straightforward then. SD promises that you pay 50% of the regular rate. So, the SD’s options are pretty much as stated – adjust regular prices and offer the 50% discount, or eliminate subscriptions. (Though they would probably be able to go back to subscriptions later and they probably wouldn’t have to offer the same deal.)

There is the possibility of an exception for economic realities, but, let’s be serious here, the damages a plaintiff or even the class would suffer are pretty minimal and I’m guessing you aren’t going to be arguing this in front of Posner.