Amazing Spider-Man #300 features the origin and 1st FULL appearance of Venom.  This is the third Todd McFarlane Spider-Man issue.  The book has become one of the most iconic of the Copper Age, and is one of the most widely-collected Spider-Man issues.  This Copper Age key book is graded 9.6 NM+ with white pages by CGC.  It has been HOT HOT HOT for decades.