Dealing with a car salesman, sure, there are tough ones, ones who stamp authority early, always lead the conversation, stern, polished, sharp and calculated.

How do you get that feeling of value for your money ?

here are some tips.
A car salesman would rather sell the car than count stock at the end of his shift. So, buyers , start demanding because he aint going to tell you what he can or cant give, reduce, or zero out.

Be professionally bullish but not ridiculously unrealistic with demands.
DO some homework around street value for options and GO LAST to the dealer you want to buy the car from - not first. Why ? its incredible hard to rebuild rapport after you had been searching for the bottom of the barrel on every option - that frustrates ppl.
Go and learn that elsewhere.
If negotiation makes one nervous, peak a salesman of near equal peer to you. The rapport builds faster , less barriers to overcome.

One mistake you can do to yourself is compare what discount values others managed to obtain vs you. That does not build confidence in yourself.
Each sale has its own characteristics and dynamics which are hidden behind the dollar value on the total deal.

Do yourself a favour. Stop comparing because there will always be someone else who paid less. Why? because one doesnt stop asking what one had paid for the same item until one finds that some who paid less. idiosyncrasy.

Art of sale is negotiation (not demands of price matching). Learn to negotiate well and you will grab a great deal.

best of luck.
Zed