Parashas Behar · Aliyah 2 · Passuk 25:14
Chabad.org — English translation + Rashi
Torah Temimah cites Bava Metzia 56b.
English: “Or buy from the hand of your fellow.” Something that is acquired from hand to hand; this excludes land, which is not acquired from hand to hand.
Classical derasha (Bavli Bava Metzia) — exclusion of real estate from the monetary laws of ona’ah.
The laws of monetary ona’ah (overcharging / underpaying that voids or adjusts a sale) apply to movable goods, not to land.