all of my Sarracenias and VFTs live outdoors year round with a few sundews in my bog. On the rare occasions they require water (only once this past summer), it comes from my rain barrel, so my water expense for my outdoor bog is zero.
Indoors, I have 2 CP stations.
One is my rack, where seeds are germinated (er...attempted) and all of my indoor dews, and one ping live along with 2 small intermediate neps. That whole setup might use a gallon or two of water per week.
The other is my 55gallon Lowland tropical terrarium, home to 6 different lowland neps. Since it's pretty well enclosed, and runs a fan to keep the air from getting too stagnant, it requires little attention from me. I open it once a week or so to water and feed/fertilize as necessary. I use about 1/2 gallon of water each week doing this.
Again, during non-freezing months, water is free. The rest of the year, it's 90 cents per gallon.