For wax, polish, wash, etc there are passable products in a lot of auto parts stores, as has been mentioned. MFs are around at a number of places but WWs are somewhat more challenging to find, especially decent ones.
Lowes carries the PC 7336 which is really the same thing as the 7424. As for getting the backplate you'll need to use it with foam pads, good luck finding that locally. Other than possibly hitting it lucky with a body shop supply, I have no idea where you'd find it in a store.
You have a phobia about ordering online or what? If you're determined, for whatever reason, to strictly avoid buying things online you have a challenge ahead of you in finding some of this stuff and a lot of the higher quality products are simply not found locally.