Bought a pile of Duetto or Spider(?) parts when I went to buy a 1750 motor years ago (I missed the car by a day). I have no use for the items and they are not perfect but in quite good condition. I am not up on the Duetto parts market but based on some scrounging around let's start here (feedback welcome):
Bonnet/hood $300
Door R $350 (has glass, chrome, top interior vinyl panel, hinge, no exterior handle/lock, one small area with surface rust)
Door L $400 (has glass, chrome, window winder and interior panel, hinge, no exterior handle/lock, one slight ding)
Cowl Air Intake Panel $150 (good with one spot of surface rust)
Front bumper R $500 (has turn signal lens and housing) and L $400 (no lens or frame for lens) Both are useable in my eyes, not perfect but would be a good polish and quite straight.
Front wheel well metal ($100 for all).
More pix available
Located in Washington, DC area and of course prefer local pick up. Local pick up will have first option.

Note I I do have a friend passing through later this week on his way back to NYC area. (gas $)?

I am willing to consider shipping at your expense but the doors and bonnet will require crating to protect them so that will need to be added to the shipping cost. Nothing shipped will happen overnight and we will need to work together a bit to sort shipping so all are happy. Pete