Commissions via web site

Gudday all
(Don’t know whether this is the right location for this question or even if I can enunicate it properly.)

On my wife’s site (based in Australia) we get requests for material to be sent to other countries . Unfortunately the postage cost means that is uneconomical for us to sent the material.
Very recently I read in the Tribune newsletter (I thinkj that was it) where a chap set up a site to provide quotes from people for other companies. He recieved a commision from each sale that the initiated. It got me thinking that I could perhaps set up something similar on my wife’s site.
Is there some information available about his type of activity?
I have no idea about about how the commission structure would work and how would you enforce it?

Is this idea plausible?