how much of a rip off are charity cards?

A question about : how much of a rip off are charity cards?

Hi
I'm interested to know how much charities really benefit from affinity cards. Taking the new Amex red as an example - it donates 1% of spend up to Ј5000 to the Global Fund for AIDS, TB abd malaria then more beyond..... but it also charges retailers a hefty amount just for the privilege of accepting the card. Does anyone know what this rate is - is it 4.5% as I have heard which is presumably why many retailers accept it, does it vary by retailer - and how does it compare to other cards - any ideas about which cards charge the least to retailers.
many thanks
(PS - my interest is as a researcher looking at how to fund health in low income countries)

Best answers:

• The amex red card is the best charity card by far.
  Amex can afford to pay 1% because they do charge retailers more.
  For Visa and MCard, the retailer pays 0.9% to the bank that owns the card and a 'merchant service charge' to cover the cost of equipment, processing etc to the bank or company that runs the card machine for them.
  Amex charge over 2% for their bank 'fee' I think, which enables them to give 1% to charity and still make a profit. The reason Amex can get away with charging more is that they argue their customers are higher spenders and because many of them have charge cards, Amex don't get the same amount of interest and fee income.
  This is why you will sometimes get asked by a retailer if you have another card - it saves them money.
  So if you are looking for an income source for a charity using credit cards, you need to be talking to amex.
  R.