Ask yourselves what you as a family would buy in the current financial situation...and also think about what is always going to be needed...food, clothing, are the obvious, and some car boots seem to allow non-branded food sales; around here (wealthy south-east) there are a number of shops thriving for some time on selling weired but cheap foreign label food, bit like Aldi or Lidl, whatever you look at there will be competetion, however small but smart could still give you a reasonable income.
One area I looked into, but decided against for logistical reasons, is the sanitarywear/nappy market, not glamorous but an essential for at least half the population. Whilst Tesco et al have their cheap ranges, and it is not perhaps the easiest buy in a public market, I think there is a potential at car-boots for packs of nappies if, as always, you can get the right price, or at least offer convenience (sorry) by being there. The old saying 'where there's muck there's brass' still holds true.
There's a bit of a baby boom going on at the moment, also at the other end of the age scale the care of the elderly requires many disposable supplies, so that would be an on-going market to explore..think about home delivery service, hygenic disposal, or supplying care homes, nurseries etc, I'm sure there are niche markets and needs to be met there.
Anyway, just a thought, I used to be a nurse so nappies hold no fear for me! Good luck
