Trumps of Doom

From Author Wars - https://authorwars.com/publications/trumps-of-doom-102021.html

Overview:

Title: Trumps of Doom
Author: Roger Zelazny
Year: Unknown
ISBN-10: 0380896354
Publisher: Avon
Price: $3.50
Pages: 184
Binding: Paperback
Type: Novel
Title Reference: Trumps of Doom
Notes:
- Undated 4th printing. The copyright page states “First Avon Printing February 1986 / Printed in the U.S.A. / K-R 10 9 8 7 6 5 4”.
- The publication date is not stated and there are no advertising pages to help date this publication. One clue is that I purchased the book as part of an Amber collection that looks like they all were printed/purchased in mid-1987 though that's not enough to define a date for ISFDB.
- While the U.S. cover price is $3.50 which is the same as the first printing the Canadian price has increased from $3.95 for the first printing to $4.95 for this fourth printing.