The Santa Monica Pier is located where the 10 Freeway ends and Pacific Coast Highway begins. It's free but parking is currently 7:00. Actually, the pier isn't "all that" but it is still a nice place to go. There is a separate costs for entering Pacific Park which is located on the pier and includes rides. I didn't research whether there is an admission cost or you just purchase tickets for the rides but you can purchase them in advance online.
There are a few places to eat including Bubba Gump's at the beginning of the pier:
and Mariasol's at the end of the pier:
If you're looking for a place to go on a date, you'd like to throw a fishing line off the pier:
or you're someone who likes arcade games and a take in a few amusement park type rides, it's definitely worth taking a stroll on the pier.:
Another reason I recommed the pier is that who doesn't like the beach? If you don't like trekking across the sand your feet don't ever have to touch it. You can lean on the rail that lines the pier and still enjoy the breeze and the view:
watch the waves crashing and just enjoy a lovely day at the beach.