In reply to Trangia:
> Personally I find profiteering out of charity shops distasteful. It's against the whole ethos of charity. If you as a knowledgeable customer see something that has been obviously heavily undervalued in such a shop, don't you think you have a moral duty to tip them off rather than attempt to profit from their error? Most charities are heavily underfunded, rely on volunteers to run their shops and can't afford to pay experts to price everything that passes through them.
No I don't. In the case of charity shops, the charity in question is engaging in the market for the purposes of fund raising. Hence they are, and should be playing by the rules of the market. Smart charities employ people to put in place mechanisms to filter the donations and price accordingly so that they maximise revenue.
AS a customer one has no obligation to the charity other than to purchase the goods at the stated price. It is a purely market transaction. If you were to say stealing from charity shops is ok that would be a completely different moral proposition.
Furthermore, there is an argument to be had that other participants in local markets, ie high streets, don't view charity shops in anything like the benign manner you suggest. Charities don't pay the same business rates for example and are potentially undercutting commercial shops.
AS to your point that 'most charities are underfunded' - I very much doubt that is true, particularly those that have a trading arm.