Sentence:  Turn off at any one of the marked picnic areas ( gasoline companies have touring service bureaus that issue booklets on national parks to tell you where you have barbecue facilities ) and - with soft drinks cooled from morning loading up , hamburger , buns , an array of relishes , and fresh fruit - your lunch <WSD>is</WSD> 75 % cheaper than at a restaurant , and 100 % more fun . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)