I once heard it’s a mitzvah to own seforim. Does this have any basis and is it true?
This is the opinion of the Rosh brought in the Tur, Yoreh Deah Siman 270, that since in our times our learning is not done with an actual Torah scroll but rather with Seforim of Chumash, Mishnah and Gemara, the mitzvah to write a Sefer Torah is fulfilled by writing Seforim of this kind.
Igros Moshe Yoreh Deah Vol. 1 Siman 163, rules that one may fulfill his mitzvah by buying these seforim as well.