2018 MARKET UPDATE:
The "new season syndrome" doesn't seem to be having the same impact on prices of WD #1 as it used to do.
Still, prices are not falling further, and there has even been a record CGC 9.9 sale recently.
I would not buy into this book now, but if (like me) you have one, hold it. Recent sales:
2017 MARKET UPDATE:
For years, WD1 has followed a pattern of hot and not, as new seasons of the hit TV series are signed -- SPIKE, debut -- SPIKE, and end -- SLUMP.
Still, the show might be losing fans over time, but collectors still want this undeniable modern key issue. CGC 9.9s have broken out of their $10,000 barrier at last, and while 9.8s have cooled a bit, they are still on many wants lists.
(Editor's note: Walking Dead #2 seems rarer by far, and is beginning to close the gap in prices on #1 in CGC 9.8. Last sale $1,427.)
TV series have a very positive effect on a comic book's value. If it were not enough that The Walking Dead has had five seasons, AMC just announced another two have been confirmed.
AMC is also behind the Preacher movie (Preacher #1 is on the Hot 100 as well).
This is definitely among the most valuable comic books of the modern era. Prices softened a bit about nine months ago, but have since bounced back thanks to the new seasons.
Stick to CGC 9.8 with white pages, unless you can afford a 9.9. Currently 9.9s are about 4.2x the price of 9.8s.