Question
Is it permitted for me to take a sefer from someone’s home on Shabbos (who normally sells it), in order to learn from it, and only pay him after Shabbos?
Answer
Yes, it is permitted to take the sefer on Shabbos in order to learn from it. However, both parties must be careful not to discuss anything related to payment on Shabbos, such as the price or any details of the purchase. The matter of payment should be left entirely for after Shabbos, and only then can they agree on the price and complete the transaction.
Sources:
Admur 323:1; 252:12; 323:8; Michaber and Rama 323:1; Mishneh Beitza 29a; [Regarding buying on Shabbos without Sechum Damim]; Az Nidbaru 11:21 [regarding Muktzah]; Piskeiy Teshuvos 306:22 [regarding Gift of Sefer]; 323:1; SSH”K 29:17-27