While the grant-making institution may come back with certain questions, you want to make every effort to address most of those looming questions ahead of time, within your proposal.
An affiliate program is a form of advertising relationship between you and a company.

Although this option is free, there are two main problems with it.

Adsense accounts are free and the person with the adverts gets paid a very small amount each time one is clicked by a visitor. Many marketers, myself included, laughingly call this "Just Over Broke.