I guess the first question i have is: What did the warranty cover? You have to read the warranty and see if it covers the fish finder. I doubt that it would be written to cover half the depth finder. If you are not happy with the boat, does it have a 30 day return written in? If so and your not happy take it back tomorrow. Do not get into a negotiation that will last past your deadline without getting an extension in writing. Written communication is your best friend in these situations. After your protected in writing, then feel free to negotiate with the dealer until you feel like your getting what you originally thought you were getting.

My $.02

No extra charge.