If you want to be maintaining long term relationships with your customers and suppliers without fear that they will try to deal with each other directly behind your back then you need to ensure that they both recognize that whatever you are charging is value for money for them.
So there is probably no percentage or dollar amount that applies to everyone.
The amount that you can charge depends upon the value that your services add and therefore what exactly you do to help each party.
Quoting from [abdulhaq55555]:
i am starting a new business, i would like to know what is a reasonable rate of commissson to charge customers for sourcing goods on thier behalf?
Quoting from [abdulhaq55555]: