Well the problem is, .pt is restricted unlike .com.pt which is open to anyone (just like .com.fr is available for those who don't meet .fr registration requirements).
The 3rd level under .pt & .fr was designed with more relaxed rules but it's worthless IMO... .pt is the real thing.
If you cater to the Portuguese market you will have a branding problem. I guess the Portuguese will expect .com or .pt, not .com.pt.
Anybody out here from Portugal who can provide us with some insight into the local market please ? :?
I don't think a lot of people really use .com.pt (or .com.fr) for 'serious' sites.
So I would say close to reg fee.