Why does the Torah add the words "v'Kam Lo"?
Rashi (in Chulin, 83a): To teach us that money acquires Hekdesh, and likewise, Metaltelim. 1
Meshech Chachmah: The field returns to be his Sedei Achuzah, and if he sells it, it returns to him in Yovel. Regarding a house it says "v'Hayah Lo", as long as he does not sell it, but if he sells [a house in [a walled city and does not redeem it within a year], the buyer keeps it forever.
Ha'Emek Davar: The field is elevated, for it was once Kadosh. Even though it was redeemed, if one grows grain in it, it is proper to sell it for Menachos. 2
Rashi: This is Min ha'Torah. However, the Chachamim decreed that Meshichah acquiresMetaltelim, and money does not.