Responsa for Bava Kamma 229:23
אמר קמאי גנב ופרע בחובו ולא בעי למיתב ליה ולא מידי הנך ארבעה זוזי אחריני שקול זוזך והדר גלימי
In the case of a sale, where the money paid was the exact amount of the value of the goods, the benefit of [a purchase in] market overt would certainly apply. But where goods of the value of a hundred were bought for two hundred R. Shesheth said that the benefit of [a purchase in] market overt should not apply,<span class="x" onmousemove="('comment',' For since he paid twice the value the transaction resembles rather a gift than a purchase. ');"><sup>39</sup></span> whereas Raba said that the benefit of [a purchase in] market overt should apply. The established law in all these cases, however, is that the benefit of [a purchase in] market overt should apply, with the exception of the cases where one misappropriated [articles] and paid a debt with them, and where one misappropriated them and paid for goods received on credit.<span class="x" onmousemove="('comment',' Cf. n. 2. ');"><sup>40</sup></span>
Teshuvot Maharam
A. A owes that amount to B. Since the court has a right to distrain a debtor's article for the benefit of the creditor, the court may surely confirm B in the possession of the book after the latter pays to A the difference between its actual value and the price he had originally paid. If B paid C for the book more than the latter paid to the Gentile, C must return the difference to A.
SOURCES: Am II. 138.