[elexhobby]

FWIW I've been told similar by Costco too, so Amazon isn't unique in this respect. My guess is that it adds some friction to the process. Refunding money is a purely digital activity, while refunding requires to you go and ship it, wait for the new item to arrive, etc, so you won't do it unless the savings are worth the time investment.

[vegadw]

I suspect this is the case, but IMHO the practice should be illegal. If you accept returns for the purpose of price reduction you should just do the price reduction directly, both for the sake of the environmental cost and as a matter of treating consumers decently.