I bought most of the Devils Due issues of G.I.Joe vs. Transformers except issues 2-4 of the 2nd volume. While looking around on the interwebz, all I can find is a hardcover omnibus version of all four versions for no less than $100. I added together the amount each issue cost individually and it comes to $55.25. How can being Hard Cover DOUBLE the price? And why didn't Devils Due release each volume indivually in TPB form?