You can negotiate anything, but understand that you won't get the new tires for free. You will have to give up something in return. You may find it's better in the long run to go for the lowest possible purchase price, then pay for things yourself.
In other words, you may wind up negotiating for a $600 set of tires, but pay $1000 more for your camper.
FROG Member MO-0008-571 Since 20124444444444My Project Blog: https://cowracer.blogspot.com/
"Camper" 2016 Rockwood Signature Ultralite 8329ss
"Casper" 2017 Ram 2500 Laramie Diesel
..ProPride 3P Hitch - "Yeah. It's worth it."