If possible, avoid seams in your roof. They don't look great, and it could lead to water getting underneath the panels. I had our metal ... the trim, cut and bend the leading end to wrap it ...

The systems have specially designed starter strips, valleys, gable trim flashing ... as much as low-end three-tab asphalt shingles, which start at $35 to $40 per square, metal roofs last 50 ...