In my opinion, it's a very good price. However, what you need to look at is the exact size and type of the dies that come with it.
It *sounds* great to have a variety of shapes to make 12" squares. However, I know that I would not use most of those dies. I tend to prefer to make other types of quilts -- such as log cabin, smaller size blocks than 12", tumbler, hunter's star, etc. I would have no use for the rectangle since it is very easy for me to cut rectangles with the equipment I have. For me, this would be a much less of a "good buy" since I would be paying for dies that I would need to store but wouldn't use.
I do think tax-free and free shipping make the deal much more attractive. Are you sure you won't be charged tax, though? It's a state-by-state thing now but also depends on location of the company. I know I get charged tax from many online stores that did not used to collect tax (including Amazon).