A week before,go by the sales managers office, generally they have a Chalkboard listing of who is ahead in sales, you want to see #2 salesman if he is close to the leader(he will deal).
My son bought his Toyota pickup truck from a multi-dealer (7 dealerships) at Mercedes-Benz dealership that was connected via internet with the other 6 dealerships.
The truck he was interested in happened to be going to auction the next week, and they transported it 90 miles at their expense for him to check it out.
It was dealer maintained (with records), carfax, one owner, and if they took it to auction, the auction house would have charged them another $400 commission.
Since he was currently unemployed they knew he had a fixed amount to spend based on an insurance check; with no trade-in due to the accident, they knew is was a "cash transaction".
The Mercedes-Benz dropped the asking price $1,000, the transport expense, and ate the $400 they would have paid at the auction house which put it in his price range.
When the salesman went into the sales managers office to dicker, he left the computer on(which included a microphone),
and he and the manager listened in on our conversation and knew that we were at out expense limit.
There were no further games, other than the sales manager came in shook hands and said "we had a deal" and incidental flaws were resolved when we came back two days later.
Other considerations: The end of the month is the best way to select the salesman you want to deal with.
Have a fixed amount you can spend,; if you have to get a loan get pre-approved at a Credit Union or co-operative, never go thru the dealership.
Anything said by you or others in the salesman's office can be heard elsewhere; if you have anything to be discussed do it off grounds away from the dealership.
If you have a trade-in, within minutes of you handing over your drivers license and they read your license plate, they have already done a credit check on you.
Let the dealership know that you are seriously looking, and be prepared to walk out at any time; we received calls the next 2 days from other dealerships where we went looking.
We have since bought this Toyota , and a Hyundai from this same dealership, always thru the same salesman, and will be looking again in the next few months. YMMV