The commitment from the Amazon founder's Earth Fund represents roughly half a percent of his net worth.
"He can afford to pitch in," Warren said.
Jason Alexander stars as Jeff Bezos.
"When your ex needs to go to space about it, you won the divorce," one Twitter user said.
The billionaire’s comments sparked criticism online.
The barrier-breaking pilot was once denied an astronaut career because she's a woman. On Tuesday, she finally fulfilled her lifelong dream.
The billionaire Amazon founder was joined by his brother Mark, aerospace pioneer Wally Funk and 18-year-old Oliver Daemen.
Oliver Daemen is set to take off on the Blue Origin flight next week.
More than 600 people already have spent $250,000 apiece to reserve a spot on the spacecraft.
"We are governed by a humbling belief that it would be better if disproportionate wealth were not concentrated in a small number of hands," the billionaire said.