My first lesson in this issue came about 15 years ago. I found a 4th printing of the first edition of A Wizard of Earthsea by Ursula LeGuin. It was library bound as well as ex library.
I found out several things that are pertinent to pricing.
1) This particular book was ONLY issued as library bound: heavy boards and cloth.
2) There was one first printing available out of dozens of first editions that was NOT ex-library. It was priced at $5000. Other first printings that were discards were in the $900-1150 range.
3) Later printings, like mine, were at 10% of that range.
So there is a rule of thumb I have used.
Your book is not as important--it is a reprint of early stories, but rules of thumb are just that.
Check with Addall, or Vialibri.net for another view of comparables. Bookfinder is an Amazon product and Amazon prices tend to the high side of a competitive market especially when one nimrod thinks his book is rare when it isn't. And the rest fall in line.
Keep in mind I am painting with a broad brush in generalizations. I know I'd pick up Lovecraft if the price was right in just about any condition and be able to sell it, so I'd decide then.
The higher the price, the longer it takes to sell and only you know how comfortable you are with whatever wait to face for the profit margin you set. Arkham House demands high prices, and fine bindings will command higher, regardless.
One final observation: on some works--particularly graphic novels with dark content--the ex library markings and such don't seem to affect price nearly as much provided that rarity (first printings or limited editions) are present and damage other than library markings are minimal.
These days, there is a shelf label, mostly an ICON, a bar code sticker for circulation on the back cover and maybe an ownership label on the FFEP. But in 1959 there were card pockets, bibliosanskrit, stamps and labels. Even if "else fine" it is still "unacceptable" as graded at Amazon.
