You can get frame sliders from any number of online retailers. Sometimes shops will carry them, but usually only common brands (vortex) for common bikes (GSXRs).

More important will be to choose the type and brand of sliders you get. Also consider getting a clutch slider.

For tires, price up dealerships, bike shop, cycle gear, or motorcycle tire shop (Ken's). You can look online, but shipping usually negates the discount