https://www.cnet.com/news/stephen-hawking-wheelchair-thesis-sell-for-over-1-3-million-at-auction/

Hawking's motorized wheelchair sold for 296,750 pounds (roughly $387,000, AU$534,600) while a copy of his thesis, "Properties of Expanding Universes", published in 1966 by Cambridge University and detailing theories on the birth and expansion of the universe and gravitational radiation, was snapped up for 584,750 pounds (roughly $765,000, AU$763,640). 

Professor Hawking's daughter Lucy said the sale gave "admirers of his work the chance to acquire a memento of our father's extraordinary life in the shape of a small selection of evocative and fascinating items."