Selecting an affiliate link

I am almost ready to launch a site featuring equine activities. Each page on this site often uses a commercial product specific to that page’s activity. I want to provide my visitor the convenience to purchase that commercial product if so motivated. (Though this is not the point of the page).

Before choosing an affiliate for the page, how can I determine[LIST]
[]Whether I can link my visitor to a specific product within the vendor’s site
[
]if the vendor uses mutiple third parties to manage their affiliation program, what criteria to use to make a selection
[/LIST]

For example, One of my proposed pages uses the Melissa & Doug Sandwich Stacking game. Going to the Melissa and Doug affiliate page shows three options: commission junction, pepperjam and linkshare. The page advises me to “review the sign up process by clicking on the network logo”. Doing so only provides a form to subscribe which is not very helpful.

Using the “contact us” link on the Melissa and Dough page garnered no response.

Any thoughts?

Regards,

grNadpa

(My sitepoint search using keyword “affiliate” points to this forum.)