I get almost all my delrin and FR4/G10 at Port Plastics. They are west coast but will ship. Depending on how much you need I would look into local plastics distributors. If you need more than $50 worth or so they will be cheaper than MSC. Port carries natural and black Acetal (Delrin) sheet and Rods, FR4/G10 in sheet and rod, as well as linen and canvas based phenolics. They also are a distributor of Atlas fibre.
Troy