I occasionally run into the problem of being a few dollars short of qualifying for free shipping when buying products from Amazon. Fortunately, I found a cool site that finds “fillers” to add whatever amount you need to qualify for the free shipping. http://www.superfiller.com/
Basically you end up getting a low priced item for “free.”
We bookmarked the site. Not buying quite enough to get the free shipping happens to us once in a while. This solves the problem without spending a lot more.