What’s a reasonable offer

I’m going to check out a 2022 Ford f150 502A Lariat package with a 2.7 ecoboost. It’s a Canadian truck imported and has a sunroof, b&o unleashed stereo, bed cover, spray in liner along with the fx4 package. Truck has been on the lot for just about 87 days and they are currently asking $43000. Miles are around 27k. I have a trade in that’s worth $2700 to $3800 trade in value. So my trade in essentially washes the taxes. What’s a reasonable offer that wont be insulting. I know it’s a business but I’m also not a charity and want to have a fair deal. 40k out the door reasonable?