And what is the zip postcode of the address with monthly rental 1297.807?
SELECT T1.zip_postcode FROM Addresses AS T1 JOIN Student_Addresses AS T2 ON T1.address_id   =   T2.address_id where T2.monthly_rental  =  1297.807
zip postcode of the address refers to T1.zip_postcode; monthly rental of 1297.807 refers to T2.monthly_rental = 1297.807;