Affiliate Marketing Secrets

I’m planning on creating my own business website, but within that site I want an Amazon Affiliate store. If I’m making money from my site from other things and running it as a business what happens with any money I get from the Amazon affiliate program?
Does the money from that count as earnings (and profit) for the business or is it a separate private income? If the money earnt from that is in Amazon gift vouchers rather than actual cash does this change things?
Thanks.