I know I used to drink and smoke years ago , and I couldn't afford to do either nowdays (even if I wanted too) .
I also know that it is very possible to live on less than £5 a week , even now !. I have done it . I just bought veg from the out of date/gone mankie shelf . It was only pennies to buy and with a peel and a scrape came up perfect. I made a huge cauldron of veggie soup that would last the week and could be added to as the week went on . I also added dried beans, peas etc , so not only did it fill me up it was very healthy too . As prices are now, you wouldn't be able to have coffee and sugar in with the £5 , but it wouldn't put the bill up that much .
It is also easy to bring the food bill down by growing your own veg , instead of chucking spidery spuds away plant them in a bucket or plastic bag...12-16 weeks later you have spuds FREE. Same with dried beans pop a few in a pot ...FREE beans.
I have done these things because at times I have had too, and others because I just wanted too. Why people who are hard up for cash don't do it is for them to work out ...I just look after myself as best I can .
Oh and as for smokers , they could grow their own tobacco , for virtually nothing. You can buy 200 seeds for a couple of quid , and each plant will give you about 4oz /100g of tobacco when dried . Very easy to grow and as long as you don't process any more than 100 g at a time , there is no tax to be paid on it . You can store 50 tons of it in leaf form , but not processed.
Once you have grown some plants , let a dozen or so go to seed and you then have enough seed to sow a 10 acre field , well in reality probably 100 times that size, you get millions of seeds from them ...been there done it .
Life can be easy and very very cheap , you just have to use your loaf a bit ....simples...
cheers
Russ