I was just there this past weekend taking my parents, but we went budget - Comfort in was $53 including taxes (using their AARP discount) and perfectly fine.
One thing you should do if you're there in January or February is see the Monarch Butterflies. The species is migratory, and the ones west of the Rockies winter over in various spots in Northern California (those east of the Rockies head just outside Mexico City). This one location outside Monterey has maybe 8-10,000 of them, all in about a dozen clusters hanging on two trees. There are so many in each cluster, all jammed along the last 2' of the branch, that you can see how they weigh down the branch! They form a tight mass in cool weather for protection, and one butterfly on the ground seemed to love resting on Dad's finger (98.6° probably helped!) The next morning when the sun was on them many were flying about and the rest were spreading their wings.
Interestingly, this generation will live about 8 months: they were born wherever, and will return and then lay eggs. Over the summer will be 3 or 4 more generations, about 4-6 weeks each...and next winter these butterfly’s great-great-grandchildren will make the return trip. How they navigate is a mystery.
The Butterfly Habitat is in Pacific Grove (just west of Monterey), on Ridge Road off of Lighthouse Ave. Lighthouse is the main drag through Monterey and into Pacific Grove; Ridge Road is maybe ½-mile beyond PG's downtown. It's pretty well marked as you get near it - once you turn onto Ridge Road there's a parking area right opposite the Buttefly Inn; you walk down an alley next to the Inn and into a small park, and the butterflies are clustered in one or two of the trees. There will almost certainly be other looky-loos there, and on weekends probably a docent as well.
There's also another habitat at George Washington Park there, but I'm told this year there aren't many at that location.
Butterflies should be there through February usually; you can call the Butterfly Hotline at (888) 746-6627. I gather this is in a private home, since I got a human at 9:30pm - so don't call real late expecting a recording!