Wait, why do you need a shop to cash a cheque? Isnt that one of the last few things you go to a bank for?

In the US, a lot of poor people (and illegal immigrants) are unbanked. But also check cashing places also tend to do title loans (turn over your car title for a temporary loan) and other sorts of "fast cash" loans with usurious rates. They and pawn shops are they type of businesses that show up in areas of town where the cost of retail spaces drop.