I always tell people that if you find a round-trip price per person of $400 or less (from California), get it now and try to get time off of work later! Book it right away because if you see online it in the morning and then wait until the afternoon or evening to purchase your ticket, the price may have gone up; sometimes, it may increase quite considerably.
This benchmark of $400 per person is if you are flying out of the Bay Area. For the most part, the cheapest flights will be out of Oakland (OAK) to Kahului (OGG), but I have also seen good deals for flights departing from Sacramento and San Jose.
Maui Moku 