Good-quality fruit is hard to find in winter, and the prices are high, too.
Literal
Good-quality [of-の] fruit [subject-が] winter [at-には] is-lacking, price [also-も] becomes-high.
不足する ('to be insufficient, lack, fall short') here in te-form 不足し connects the first clause (water shortage) to the price rise. も adds 'also, too' to 値段 ('price'), emphasizing both consequences.