Let's say I were to refer somebody to Amazon.com to buy a certain car stereo and they wander through the site and decide to purchase a different one. Since I referred that person to Amazon.com will I still get credit or would I only get credit if they purchased the product I referred them to. In a different case scenario let's say they were to purchase the item I referred them to as well as other items that aren't related to that. Would I get credit in that instance?
If they bought other items including the one you referred them to yes you get the credit. I see this quite often. For example on my website reports I can see someone clicked on a stroller link. Then while they are there they picked up a few childerens CD's and some diapers in the amazon reports. I think the cookie is only 24hours.
no, they only give you credit for purchase from the country you are an affiliate of. If you have a USA visitors that orders from The USA amazon then yes you get credit even if they buy a different product than you linked them to. But if they buy from the Japan, Germany... amazon you get nothing.
Also keep in mind, they are starting to limit some very popular items and not allowing commissions on them. For example, the Wii no longer qualifies for commissions.