Both United Airlines and JetBlue have round trip airfares travelling to and from Boston (BOS) and San Francisco (SFO) for $216, nonstop. The United flights are on a basic economy airfare so choose JetBlue for sure to get the better valued flight where you may have two carry-on bags for free. Google says 27% fare increase likely in 12 hours.
Virgin America have this for $10 more, with a wider availability than below. Still a great price and for main cabin.
Departs BOS: Dec 4, 5, 6
Departs SFO: Dec 4, 5, 6, 7
Returns: good availability wtihin 7 days, or up to Dec 14
Use those dates and plug into Priceline [priceline.com]
, Orbitz [orbitz.com]
or Expedia [expedia.com]
to see which airline is flying on your choice of dates. Bundling hotel with airfare will save money.
Side note: Some travel deals start in the Travel Deals & Discussion Forum
now, so don't miss out! follow me or find recent deals there.