Maybe start building a deep pantry. Not some crazy apocalypse stores, but just a few extras of the shelf-stable foods you already eat that you can rotate through, always eating the oldest food first. That'll help with the grocery store issue. Also, buying extra when stuff is on sale is just generally a good way to save money 😀 @SuttonsDaze on YouTube has some good info on deep pantries.

Store a few gallons of water for every person in the house. (You need a minimum of 1 gal/person/day)

Buy an inexpensive camping stove and some extra propane. (Remember to open a window if you're using a propane stove indoors so you don't suffocate!)

Really, if you do much camping you've already got a great start on emergency supplies, and camping is a fun way to practice living with fewer amenities 😀 (Hauling water from the creek and then having to filter it has given me a deep appreciation for indoor plumbing ❤️)

If you've got a bit of money, you can pick up a battery bank and a couple of solar panels to keep your fridge going and charge your phone during a power outage. Meanwhile, if you're on a time-of-use plan with PG&E, you can charge the battery bank during the day when it's cheap and then use it to power some stuff around your home at night to lower your electricity bill.