I own some land in rural TN, with a winterized trailer and access to spring water. that is backup water and shelter for minimal cost. A person/year of shelf-stable food (not fun, but indefinitely survivable) is about $1000. So if I am smart about it, and fall back gracefully, every $3k-$4k in savings is a year of "backup survival". I still need to make sure I have at least a year's worth of currency in a liquid form in case of infrastructure or banking collapse and ideally at least 6-months food dry-packed on site in case purchasing food while falling back is not viable.

just a reminder, there is a lot more to back up than your hard-drive.