In the shops where I can get it, they have it in a separate aisle for vegan and gluten-free foods.

Could also be nearby to tofu, so potentially in the Asian food section (even though TVP isn't an Asian invention).

If your store has a Bob's Red Mill section, it might be there.

I'm a big fan of TVP in spaghetti sauce, to give a bit of chewy texture. You can also use it to replace the meat in shepherd's pie, or anywhere else ground meat provides texture but is overwhelmed by other flavors.

The shelf stable aspect is a huge selling point for my household.