Does the implied warranty of merchantability include shipping costs?

I bought an item from a “sold by” seller on Amazon.com. It did not function properly when it arrived. I called the seller (a company, not a person) and followed their instructions to try to get it working. I was unable to get it working. The return label assigned via Amazon is not prepaid via UPS, etc. I went back to the Amazon page for this item and read the seller’s warranty policy. It reads: “5 years warranty for parts and labor. Buyer covers round way shipping cost.” I wish I had noticed this before I made the purchase. I paid for shipping it back to seller. I have not received the replacement yet.

The implied warranty of merchantability says that the item must function properly for the intended use. (My paraphrase.) Does the implied warranty of merchantability also include costs to ship to/from the seller if the item doesn’t work from the very beginning? Both I and the seller reside in California, if it makes any difference.

In this case, I called Amazon and, as a goodwill gesture, they refunded my shipping cost in the form of a credit for future purchase. As long as the replacement works properly and the seller doesn’t charge me to ship the replacement, this is just an academic question.