In my own experience, D. capensis and D. spathulata can tolerate
relatively low humidity, especially if their pots are set in water,
and these plants also tend to glut themselves on all available
insects. P. caerulea is also tolerant, although it seems to like it a
bit wetter when it's flowering.
For your location, the best mail-order would probably be California
Carnivores, located at 7020 Trenton-Healdsburg Rd, Forestville CA,
95436. Their telephone number is 707-838-7397.
I don't know what experiences others have had with them, but with me
they've always been efficient, friendly, and very helpful (although I
haven't gotten their spring price list yet).