If you're ok with a hotel room you can get a nice hotel (Westin/Sheraton/Hyatt) on Kaanapali beach for under $200 per night on Priceline typically. I'm biased toward the Westin Kaanapali Ocean Resort Villas (not the Westin hotel) - it might well be my favorite vacation resort in the country. It's on the sleepier end of Kaanapali beach, but that end is better for snorkeling. The nice thing about the Villas is you've got a kitchen and a washer and dryer (which comes in very handy for wet and sandy swimsuits at a minimum). If you work hard enough, you can score a 1 bed unit (I personally wouldn't settle for a studio) for about the same price that you would pay for a hotel room. You can find listings for these on redweek.com, tug2.com, or even on vrbo.com.

Alternatively, the Honua Kai resort is right next to the Westin Villas and is very comparable. Lots of listings for that one on vrbo.