Table schema:
CREATE TABLE WINE (Price INTEGER, Appelation VARCHAR); CREATE TABLE APPELLATIONS (Appelation VARCHAR, County VARCHAR)

Question: Give me the average prices of wines that are produced by appelations in Sonoma County.
SQL: SELECT AVG(T2.Price) FROM APPELLATIONS AS T1 JOIN WINE AS T2 ON T1.Appelation = T2.Appelation WHERE T1.County = "Sonoma"