Can the merchants claim it as a donation on their taxes? At least in Germany, you can't "pre-donate", i.e. work to a charity and claim it as a donation. You'll

Can the merchants claim it as a donation on their taxes? At least in Germany, you can't "pre-donate", i.e. work to a charity and claim it as a donation. You'll have to agree on a price and the charity has to be able to compensate you and after everything is done, you can choose to not take their money. I'm not sure whether the third party in the transaction changes anything.