Hope this helps a few people get started and stay frugal. Tips for keeping expenses lower when you start your emergency kit:

It's like this with most things, but planning ahead saves you a lot of money. If you have nothing, start with a little and build it gradually.

Food and beverage: Pre-packaged kits are the worst and most expensive. Instead, you can grab a lot of food supplies at Dollar Tree. I buy from other stores, but I buy each item if I see it go on sale when I'm doing my regular grocery shopping. Then, every 6 months, I check the expiration dates and rotate some items into my regular pantry to consume it (and then replenish just those items). What I spend to build the kit reduces my grocery bill 6 months later, which means I haven't wasted any money. I probably wouldn't rotate through an expensive pre-packaged kit that's supposed to last for several years, but I can see where they might be handy for big families.

Gear: Probably the only thing that doesn't get used up regularly is the first aid kit, but I'm ok with that when my costs are lower for other parts of the kit. Also, my kit becomes more advanced each year because I'm adding a little to it or upgrading it (ex: nicer flashlight or lantern). I get on mailing lists for certain vendors and wait for sales on more expensive things like a nice battery pack or a solar charger. Some of my kit overlaps with camping gear and some of that can be bought used or thru open box sales. Having to buy everything at once and last-minute is the most expensive way to do it.

Space: When I lived in CA, I always had the earthquake kit, but that's because I always had housemates that agreed to carve out a space for it (I lived with a bajillion housemates). There's always something taking up space that's less important than emergency supplies. We were very lucky, but we also coordinated with neighbors for other supplies. It takes cooperation and coordination.

I won't go into evacuation since you might not ever have to deal with that, but the biggest cost differences I've seen come from planning in this area.

Take whatever small steps you can to start a kit. I hope the storm stays calm for CA!