While I'm a huge believer in this book longterm, it does seem like there is some over-inflation on 1st, 2nd and 3rd prints going on right now. I think I saw a signed 3rd print in 9.0 sell for over $300 the other day. That's crazy. I expect there to be some pullback after the movie hype dies down and then TMNT 1s will go back into their slow, steady incline.
My copy is only a 5.0 (but a pretty one!) and for a while I didn't know if the price I paid was decent or not. I bought it at the tail end of 2012. Now I can safely say that I paid a great price