Cards on the table - I'm a volunteer at a charity shop. One of the large ones which has branches nationwide.
We have one regular "customer" who is nicknamed the Smiling Assassin by the volunteers because she comes in a lot (3 or 4 times a week), smiles and says hello to everyone, then spends the next 5 minutes bitching about the prices. She rarely buys anything. She is of the opinion that our shop is there to provide her with cheap stuff. Cheap as in 50p for practically everything. She is horrified when volunteers explain that we're trying to raise as much as we can for the charity, and the best way of doing that is by pricing realistically - not giving away Jaeger suits or "mother of the bride" type outfits for £1.
She was particularly horrified and commented loudly on a bracelet we have in the cabinet priced at £170 - it's antique, 18 ct gold, emerald and sapphire, and has been valued by a jeweller. We would be daft pricing it at £19.99, even if it is the most expensive item in the shop by a long way
So anyway, what do you think charity shops are there for - raising money or providing cheap things?
(Disclaimer before everyone starts about their local charity shop which prices bobbled Primark tops at £29.99 - mistakes happen, stuff slips through the net. Even if the manager has a "price to sell" policy, she/he isn't going to check each and every item and some items will be priced too high or too low by well-meaning volunteers.).