In a shtf situation to survive you need shelter water food in that order. i think in an economic collapse so many people will be upside down on their mortgages that the banks will give up on collecting their mortgage payments it will be so wide spread that people will just occupy their houses squat that is .Thats shelter covered .I most places there is a natural sources of water about river stream pound the only problem is to make it drinkable that is to purify it ..You can stock up on food now but with millions of people not preparing and then going hungry your going to have to share that food either willingly or not so its not going to last long , The solution to this is to hunt trap fish forage and long -term homestead .In most areas there are sources of fish rabbit or pigeon. Well take procuring them sepritly
water you can purify water with cheap clear platic bags you can buy cheaply in bulk now
heres an cheap easy way to purify water
Fish
In advance you can buy bulk fishing hooks in the 500s for a few quid and a long reel of fishing line
Rabbit in advance you can buy bulk rabbit snare wire
here is how to snare rabbit
Pigion
In advance you can buy 1000 meters of paracord to make bird traps
Here is how to make a bird trap
For foraging wild plants a particularly good cheap little book is the coilns gem book food for free
For a more permanent food source long term a good book is grow a sustainable diet
For generally liveing off grid the book the earth care manual is the book to get
Heres a bonce
you can buy in advance bulk reels of candle wick from which with cooking oil you can make lamps to light and cook
If you woundering why i am suggesting you need to preppers watch this video