Metal Roof and Underlayment

I live in Florida by a saltwater canal. I have estimates on a 5v gavaloom and standing seam is about $10,000 more. What is the best cost effective metal roof? My second question is what is the best underlayment for a metal roof: felt, synthetic, self-adhering or a combination of both? Thank you for your assistance in this matter.

Call roof repair pompano beach, they will tell you the actual cost of it.