The following links are various resources to buy gear. It is a guide, and not strictly endorsed by the Duchy of Chesapeake.
Chivalry Sports: Arms, Clothing, Books, Accessories
The Tudor Shoppe: Arms, Clothing, Accessories
Garb the World: Clothing, Accessories
The Armory: Arms, Clothing
By the Sword: Arms, Clothing, Books, Accessories, Archery
Purple Unicorn: Clothing
Half Moon Cloaks: Clothing
Renaissance Magazine: Magazine devoted to the Renaissance period.