There is often a fine line between crime, commerce and even altruism. It is a shame that western society has been perhaps a little too effective at separating these concepts. The very same contract could be any of them in different contexts:
"Party A pays 1 Pound Sterling for the item owned by Party B"
Crime: Party A blackmails Party B into selling them the item at a discount
Commerce: Party B offers the discount to entice Party A to try the item out, so that they can sell more at full price in the future
Altruism: Party B wants to give the item to a good home rather than destroying it (if that would cost them, then it's even mutually beneficial altruism from both parties)
Clearly it is the context about how the contract was made that distinguishes the situations. It would be a mistake to try to classify every possible contract as legitimate based on its semantics alone.
"Party A pays 1 Pound Sterling for the item owned by Party B"
Crime: Party A blackmails Party B into selling them the item at a discount
Commerce: Party B offers the discount to entice Party A to try the item out, so that they can sell more at full price in the future
Altruism: Party B wants to give the item to a good home rather than destroying it (if that would cost them, then it's even mutually beneficial altruism from both parties)
Clearly it is the context about how the contract was made that distinguishes the situations. It would be a mistake to try to classify every possible contract as legitimate based on its semantics alone.