Look, I'm not at the bottom of the pile ... at the moment; the threadbare rug can be pulled from under your feet without warning. Perhaps unwisely, I thought I might share some of my massive fails with you. Just in case (unlikely as it is) it might help anyone get a smidgeon more insight into how things go wrong.
I smoke. I can't afford it, and am giving up. My 'bonus' allowed me to buy a vaporiser kit and the stuff that goes with it - I've got 3 months' worth. Total cost £135. It was the extra money that permitted this provision.
I'm finding it impossible to switch from tobacco to vape at the moment, because I've been given notice on my house and can't afford to move. Anxiety is stratospheric. Unfortunate that I'm an addict, but I am, and it's well enough known that addictions intensify during stressful times.
I have mental health issues. As part of these conditions, I dissociate when I can't cope. I can find I've 'missed' ten days while achieving nothing whatsoever, and also that I've spent money online. Sometimes I can persuade a seller to cancel an order, but often I can't. I end up selling things I was convinced I urgently needed, for less than I paid.
Another aspect of my MH is an inability to deal with paperwork: forms & suchlike, funding applications, etc. Despite my high literacy & numeracy, phrases jump about on the page/screen; I lose basic maths ability and objectivity; I cannot express myself properly.
I have CFS/ME. From my current home, it's a short walk to Aldi - which is a total diet lifesaver - but I can't walk anywhere on about a third of my days, and can only manage to cook about one day in four.
I'm (medically) dairy intolerant, have a couple of severe food allergies, and my health conditions mean I should never eat pulses or soya. I do use them because of the cost savings, but it isn't helping my health. I need a high protein diet - just ate a value scotch egg in Aldi as I was about to pass out.
I have no social life at all. It's all online. Because I miss going out, I drink a couple of cans of own-label beer in the evenings while talking to you lot.
You'll be pleased to hear my 22" flat-screen telly was £50 from ebay 
I'm BETTER placed than most down here in the underclass. I'm intelligent & educated, I own fabulous cooking kit from when I was well-off, have extensive knowledge of nutrition, my mum bails me out with food parcels, and I can walk to Aldi. I've received a few large payments that facilitated everything from a new coat to beating down my mobile & broadband subscription costs. My mobile's 5 years old. I got an upgrade with my 'bonus' and immediately sold it.
So what I've just described, above, is what a PRIVILEGED life in the underclass looks like. Take away any one of my privileges, and the fall is far & steep. Yet, privileged as I am (relatively), I'm still facing homelessness. My mother will probably save me, because no-one else will. It's a bloody miracle she's still alive, thank goodness, because at my age I should be bailing my grandchildren out!