Flights at this price point are available on Tuesday, Wednesday, and select Saturday starting in mid-January through March 13, 2019. Tickets must be purchased by midnight, January 7, 2019.
As an example, I found seats departing SFO on Wednesday, February 13 and returning from MCI on Wednesday, February 20, 2019.
Alaska Airlines has a lot of great deals today so make sure you see what other destinations are on sale if you're still looking for a last-minute getaway/gift.
Need a place to stay while in Kansas City? Here's a list of available accommodation via Hotelwatchdog.