Amex is a huge cost for small businesses. I remember it being something in the vicinity of 5-6% of the purchase price in costs for the retailer and if you are signed up to an association similar to the retailers association. It is higher if you are not, from memory 8-10%and also not all banks do this. Kiwibank was offering 4-5% for Visa or Mastercard for the retailer. I believe They don’t have an association that can make it cheaper.