Amen to this.
The charity bashing on MN is tiring (and prevalent).
Charity shops pay full rent. They pay full utilities. They pay full salaries and volunteering costs (insurance, training, welfare etc).
They price items for what they will sell for. If they sell too low, then I 100% guarantee that it won't be bargain hunters or 'the poor' who can snap up a bargain. It'll be traders on the lookout for items they can flog on Vinted.
They are obliged to sell for for the best price they can achieve. Their sole reason for existence is to raise money for the cause they are associated with. It would be against their constitution to sell for prices purely to benefit the community.
They are generally inundated with tonnes of stuff that is simply unsellable. In order to discover its unsellable, staff and volunteers have to sift through bags containing some pretty dubious items. It's not a task for the faint hearted.
Charity shops are for the good of the cause. They provide an opportunity for people to make a financial contribution to charity. They provide volunteers with an opportunity to be involved in their community. And, in my personal experience, have provided some wonderful people the opportunity to rebuild confidence after long term unemployment, or poor mental health, or widowhood, or developing skills etc.