Well, do you want to be close to the beach, so that you can walk to it? Those are mostly mid-range motels where you would need two rooms. Or more expensive bayfront properties.
The ones right on the beach are going to be expensive. Some of the ones a few blocks away are in not too desirable areas.
Here are some choices. Carousel Motel..kids under 16 stay free, Boardwalk discounts, Continental Breakfast. (800) 214-7400, santacruzmotels.com. (This may be your best bet.) two AAA diamonds.
Comfort Inn Beach Boardwalk (no website, google them) 2 diamonds
Ramada Limited, Fisherman's Wharf. This is in a very good location, on a hill above the Wharf (not a "fisherman's wharf", but what does AAA know? Two diamonds.
Santa Cruz Beach Inn, 4 blocks from the beach, three diamonds. This one looks good. "Book great rates at AAA.com"
There are also two Super 8's and two Travelodges.
My favorites (the expensive ones) are Coast Hotel Santa Cruz and Sea and San Inn.
try santacruzmotels.com and see what you think.
Have fun googling.