Big O Tires stores in Southern California and Las Vegas are running a Buy 2 Get 2 Free tire sale through Monday, February 20th.
When you purchase four tires with an alignment and tire protection plan (includes roadhazard warranty, free balancing, free rotations, free flat repairs, roadside assistance), you get two of the tires for free.
My local store in Southern California includes a one-year alignment in the package which means you can come back as many times as needed within a year to have the alignment re-done, say if you hit a curb or large pothole.
A set of four 100,000 mile rated Sumitomo Tour Plus tires for my Prius comes to $423.96 which is a solid deal for all that's included in the package, plus this particular tire has a 100k warranty.
Also, if you pay with your Big O Tires credit card you can save an additional $50 for purchases $500 or more via mail-in rebate ($25 rebate for purchases $250-$499).
Southern California: Link [bigotires.com]
Las Vegas: Link [bigotires.com]