Our family went to Santa Monica just before Labor Day weekend. We spent some time walking around the Third Street Promenade and visiting the children's sections of the bookstores there. Then we drove to the Santa Monica Pier and parked for $8 in the lot on the north side of the pier. There is a small amusement park on the south side of the pier called Pacific Park. In addition to some larger rides for adults and families (like a large solar-powered Ferris Wheel, a fairly tame but large and noisy roller coaster, bumper cars, and a large dragon swing), there is a smaller area on one side with about six to eight smaller rides for younger children.
On the weekday we visited, the all-day wristband for children was $10, and we got a 15 percent discount with an online coupon. Our kids had a lot of fun riding the biplanes (like the Dumbo ride at Disneyland), the miniature trucks (they have steering wheels, but you can't steer), and the swinging submarine. The bumper cars also have a separate space with little bumper cars for smaller children, although our preschooler son couldn't figure out the steering.
Separate from the amusement park is the historic Looff merry-go-round, which is very reasonable at $1 per adult, with one child under 6 free with each paying adult.
