Market stalls, for a lot of bits & pieces... vacuum cleaner repairs, small quantities of bolts, screws, etc., cheap tools for an odd job, adhesives, wire, garden bric a brac .... you name it, there was a stall somewhere that sold it. Certainly, for computer and electrical components stalls existed in the 80's.
I've just ordered an in-line light switch, 99p delivered. I'm sure a DIY "shed" would sell me one for a fiver, or Toolstation for £2. Ebay; 99p all in. In the 1980's I'd have (did) pick these up from a market stall in a small rural town.
I suspect many stall-holders also run an Ebay outlet nowadays ... or maybe just run an Ebay outlet!