San Francisco to Cancun $218 RT "all in"

Spotty availability on this deal...but it's definitely there. Mexicana Airlines is offering a $121 + tax fare SFO-Cancun; comes to $218 RT with taxes. Travel is valid now (w/14-day advance purchase) through May 2011. Visit www.mexicana.com to check availability, including the flexible dates calender. Note: I found fairly good availability for February (example: February 7-12, 2011).