Interchange is all over the place. It can easily go to 2.5%.

http://www.mastercard.com/us/company/en/whatwedo/interchange... http://www.mastercard.com/us/company/en/whatwedo/interchange... http://www.mastercard.us/merchants/support/interchange-rates... http://www.osc.nc.gov/secp/schedulec-visaandmastercardiqda.p...

The rules are very complicated and arbitrary. To give you an example: cashback interchange in Poland is negative (acquirer get money from the issuer), intradomain interchange is positive (issuer gets money from the acquirer) and interdomain interchange is zero.

There is no way explain interchange without using the words yacht, golf course, hookers and cocaine.