פירוש על עבודה זרה 108:6

The one that holds that animals used in exchange for animals used to acquire an idol are prohibited uses the word “it” (“it” is prohibited and not things exchanged for it) to exclude orlah (fruit during its first three years of growth) and mixed seeds planted in a vineyard. One may not derive benefit from either of these. But if one sells them (this is prohibited) and then uses the money to betroth a woman, the woman is betrothed. This proves that this money has value to its owner.