I need to cover a metal roof and a BUR roof in New Mexico. My contractor had me purchase 5 gal of Ames Snow Seal for the carport metal roof, which was around $150. There appear to be other types of elastic roof sealants out there which are much less expensive. However, I tend to believe that you get what you pay for. I wonder how the cheap sealants will stand up in our very hot summers and cold winters. Any experience with these products? The BUR roof will take maybe 3 five gallon buckets.