I see people giving away their products and they put affiliate links through out the product.  They think that by giving it away that more people will read the product and they will get more affiliate sales.

That sounds very logical and it does work — to some extent — but then many of the marketers who give away their products for free sometimes can't justify the time and effort spent in creating their products.

Well, they may be right about one thing. More people may read their product, but there is no guarantee for that — There are plenty of products that cost money that are seen by way more people than free products. 

A problem that these marketers encounter is that there are a lot of freebie seekers out there.  Sometimes many of those who downloaded the free products are exactly the kind of people who wouldn’t of been willing to pay for a product in the first place… so would they be willing to pay for the products that you’re promoting?

However, if your free product is distributed to an exceptionally large crowd (which is not the usual case), even though the purchase rate is low, you may still make good affiliate income from it. But then again, don't be mistaken and draw the wrong conclusion that free products equal more affiliate sales.