Some sites I have purchased things from:

www.jamestowndistributors.com
www.mertons.com
www.mcmaster-carr.com (Not boat specific, but they have EVERYTHING general)
www.tendercraftboats.com (Some windows, fasteners, nice fairleads, etc.
Cheap Canadian prices)
www.stright-mackay.com (Bought rub-rail there, again cheap Canadian
prices.)
www.Bethel-Marine.com (Lowest price on some electronics I bought)


Some of these MAY not be the correct web address. If not, just GOOGLE for
the company name and you'll correct whatever spelling or other mistakes
I might have made.