Good charity shops are hard to find, but they do exist.
I generally avoid the chains- they have a lot of paid staff and very inflexible on pricing.My local indie shop is staffed 100% by volunteers. The shop is in a small town with a good smount of social housing, but also many affluent areas too.
The shop is always busy, packed full of items to sell, and gets tons of donations too. There is usually a small queue at the till.
I visit once a week at least, often twice and each time I go it is a whole new set of goods on the racks and shelves. Stock turnover is vey high, because prices are very low.
Like other shops they sell kitchen equipment, crockery and glasswear, books, clothes, baby things, decorative and seasonal items, craft stuff, wool, jewelry, linen, basket wear, small garden equipment, tools, pots, and random things like fishng tackle, ice skates, LPs, mirrors, pictures, small pieces of furniture, suitcases and bags, old magazines, camping stuff.
Clothes are all priced at £1 except t shirts and smaller items which are 50p. Good quality clothes like a silk dress, woolen suit or cashmere coat will be priced at £3, but all staff are authorised to cut the price for defects like stains or missing buttons.
Last year the shop raised £450,000 in profits which were donated to local charities.