Housing Works Bookstore Café, Soho, Manhattan
Update - At the moment, the bookstore/café is closed. It seems hopeful that they will reopen when the pandemic slows down.
I regularly visit the Housing Works Bookstore Café. They sell secondhand books which are donated by people who care! "Housing Works is a healing community of people living with and affected by HIV/AIDS. Our mission is to end the dual crises of homelessness and AIDS through relentless advocacy, the provision of lifesaving services, and entrepreneurial businesses that sustain our efforts." So by shopping and donating to Housing Works you are also giving to those in need! I often find books to buy there and it certainly feels good doing so!
Housing Works Bookstore Café, 126 Crosby Street.