We had seen the model we wanted at a dealer about a month before a large RV Show. At the show we shopped two different dealers for the same model and got quotes from both. We called the original dealer (they weren't at the show) and told them what the show dealer quotes were. The original dealer offered the unit for $2000 less than the lowest show price offer. We left the show and went over to the dealer and closed the deal.
By the way, that was over 20 years ago and all of the phone negotiations were done over one of the original brick type mobile phones. First time it was worth having.