Woods County Park

From their official site, it's $33/night.

A decent haul to the beach from here, as you have to walk along the river and then back up a couple miles total to get to the stack and sand dune, this park is essentially a more cramped version of the Webb County Park, which is just across the street from Pelican Brewery and the main beach area. We went there instead and recommend you do as well, they at least have showers and bathrooms, not to mention access to the main attractions here in marvelous Pacific City, Oregon.