One of the best deals in travel has long been the annual Alaska Airlines $99 companion ticket that comes with their credit card, since it's valid for any seat on any flight in conjunction with a paid ticket without restriction - and even earns miles. It's coach-only, which wasn't always the case (buying one first class Hawaii ticket from the East Coast and getting the second for $99 plus tax was once a great deal), but other than that you can do almost anything you wish.
Right now though Alaska Airlines is offering companion travel without the $99 payment, without the credit card, and in unlimited quantities.
Book a flight for travel through October 31 and the second passenger costs just the taxes and fees. Alaska is blocking middle seats, so it doesn't really matter much that this is coach - two travelers get a row to themselves. And since there are currently no change fees (so far Alaska's policy for new tickets runs through purchases made by September 8) so you retain full credit if plans change.
You have to book by Sunday August 9 at 11:59 p.m. Pacific time using discount code GETTHEROW on the Alaska Airlines website searching travel for two passengers. The discount code yields 50% off the base coach fare of both passengers' tickets.
There are a few restrictions:
This strikes me as a genuinely good deal, and we have seen surprisingly few of those despite plenty of available seats.