ROTFL
Sorry to disappoint you but an AMIGA Zak Mckracken goes for usd200-250, and here in Europe they seldom sell for more than €200 and only for copies with Mint boxes.
I see a rip on your box and it seems you are missing the internal plastic display as well...
Also consider that the Amiga version is definitely the most common among all versions and I doubt You will make more than €175.
Only German, Italian and Japanese versions sell for top $... the UK and USA versions of the game are far more common.
In the last few years I built a large Zak Collection:
Zak McKracken and the Alien mindbenders PC Floppy 5 1/4 & 3 1/2 ENG USA
Zak McKracken and the Alien mindbenders PC Floppy 5 1/4 & 3 1/2 ENG UK
Zak McKracken and the Alien mindbenders PC Floppy 5 1/4 ENG UK 384kversion
Zak McKracken and the Alien mindbenders PC Floppy 5 1/4 & 3 1/2 ENG USA 384kversion
Zak McKracken and the Alien mindbenders C64 Floppy 5 1/4 ENG USA
Zak McKracken and the Alien mindbenders C64 Floppy 5 1/4 ENG USA
Zak McKracken and the Alien mindbenders C64 Floppy 5 1/4 ENG UK *Different front label
Zak McKracken and the Alien mindbenders AMIGA Floppy 3 1/2 USA
Zak McKracken and the Alien mindbenders AMIGA Floppy 3 1/2 ENG UK
Zak McKracken and the Alien mindbenders ATARI ST Floppy 3 1/2 USA
Zak McKracken and the Alien mindbenders ATARI ST Floppy 3 1/2 ENG UK
Zak McKracken and the Alien mindbenders FM TOWNS Cd Rom JAP
Zak McKracken and the Alien mindbenders C64 Floppy 5 1/4 ITA
Zak McKracken and the Alien mindbenders C64 Floppy 5 1/4 ITA
Zak McKracken and the Alien mindbenders AMIGA Floppy 3 1/2 ITA
Zak McKracken and the Alien mindbenders PC Floppy 5 1/4 e 3 1/2 ITA
Zak McKracken and the Alien mindbenders AMIGA Floppy 3 1/2 ENG UK KIXX
Zak McKracken and the Alien mindbenders PC Floppy 3 1/2 ENG UK KIXX
Zak McKracken and the Alien mindbenders ATARI ST Floppy 3 1/2 ENG UK KIXX
Still looking for...
Zak McKracken and the Alien mindbenders FM TOWNS Cd Rom JAP variant version with newspaper
Zak McKracken and the Alien mindbenders AMIGA Floppy 3 1/2 GER
Zak McKracken and the Alien mindbenders ATARI ST Floppy 3 1/2 GER
Zak McKracken and the Alien mindbenders C64 Floppy 5 1/4 GER
Zak McKracken and the Alien mindbenders PC Floppy 5 1/4 GER
Zak McKracken and the Alien mindbenders ATARI ST Floppy 3 1/2 ITA
Federico