That really depends on which brand you want and where you live. Iím east of the Mississippi and Iíve ordered Dunlopís from Race Tire Service and Pirellis from Sportbike Track Gear. Decent prices and fast shipping from both. I get the same price from the vendor at the track though so thatís where I usually get me tires from now.
I get my Pirellis from Trackside Tires. They have two locations that ship and its fast. Prices are good also.
I just picked up a set of superbike slicks SC2 few weeks ago for CCS race. https://tracksidetires.com/