On a budget, Sutro Baths Ruins still earns its price.
Free
Atmospheric, sea-battered ruins of a once-enormous glass bathhouse, with tide pools, a clifftop cafe, and a cave — moody and free, right at the start of the Lands End trail. The catch: the rocks are slick and the cave can flood, it's almost always cold and foggy, and there's not much beyond the ruins themselves.