I use Google Shopping (the “Shopping” tab on Google) to see if local stores carry certain products, what they cost, how far away each store is, etc. It seems to mostly search national or large regional chains, but it was still pretty useful.
Is there any alternative to this (in the US)? The “nearby” function has unfortunately got shittier and shittier over the past year or so. It’s gotten less “deterministic," just mixing results from local stores with e-commerce stores, further reducing usefulness.
This is not a general answer to your question, but many times if I go to the original manufacturers website they will tell me where I can find their products locally. Failing that you could bite the bullet and call the manufacturer. They should have a distribution database that can answer your question. I’m going to watch this thread to see if someone has a real answer eventually.