[quote name='panzerfaust']Sounds very reasonable, though I'm surprised the CE guide didn't become more valuable -- it's so nice

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You gotta look at it like this... There were 210,000 FFXIII Collector's guides made. As a comparison, the MGS4 Collector's guide only saw 43,000 published. Of course, the FFXIII is on two platforms while MGS4 was a PS3 exclusive. Even so, if we doubled that number to compensate, we'd still only have 86,000. That guide came out a little over two years ago and can still be had pretty easily for around the MSRP. Plus, while the FF guide looks nice, the MGS one looks just as nice(if not nicer, IMO) and it came with a pretty sweet print of Snake.
So, while the FF guide sold out online, it doesn't surprise me that it hasn't inflated in price... It's really just not that limited, and it's only been around for about 4 months.
To answer the OP's question, that seems like a great deal to me. If the items in question are in perfect condition, I could even see them going for a bit higher than that.