Do any copies of the Gutenburg Bible still exist? Could you actually buy a Gutenburg Bible? Assuming you got enough cash, do they actually come up with for sale?
From, "The Top 10 Rare Books" https://entertainment.howstuffworks.com/arts/literature/10-rare-books1.htm:  


"It is believed that 180 copies of the Bible were produced--135 on paper and 35 on vellum, or calfskin.  Today, only 48 copies are known to exist, some of them only partial, almost all of them in the hands of museums, universities and libraries..."  
"How much is a Gutenberg Bible worth?  A perfect copy hasn't changed hands in years, but in 2007, a single leaf went on sale for $74,000.  In 1978, Christie's auctioned off a perfect two-volume Bible for $2.2 million.  Another Christie's auction in 1987 transferred an incomplete version to a Japanese company for $4.9 million..."