The hang onto their keys for 2 hours thing is the oldest trick in the book. They'll make it even worse if you bring a kid with you. The idea is that you'll be so flustered by the end that you'll just sign the papers to get out of there. It sounds ridiculous, but it really is a sales trick.
The closest big dealership to me lost my business for life because of stuff like this.
Seriously - man - if they want my kid in their dealership wreaking havoc...fine with me. (Although D is now 15...) If I had DD with us at the dealership when she was little, and the dealer messed with me...I would have let my kid loose in the showroom.
They would have begged me to wrap the deal up at MY terms.
Really...always do your homework. Always keep the purchase price of the car separate form the trade-in value of the old car. Never allow them to "hold on to your license", always give them a spare key for the vehicle. That way, if you need to get up and walk...you can.
My DH and I purchase a new vehicle about every 4 to 5 years. The last vehicle, a Ford, we did most of the negotiating on it on-line, and then came in and test drove it. That particular day, we had a very specific timeline, since DD needed to be picked up at practice. dealer knew the time line, and at 1:30, the sales rep was pretty surprised that 90% into the deal, I put on my coat and stood up. Clearly, I needed to go. The deal was wrapped up in 5 minutes. Dealer did not know that DH and I arrived in separate vehicles. dH stayed and finished up the paperwork.
Always do your homework on the vehicle. There is SO much info online right now. Know what you want to spend. Trade-in's are a bit of a wildcard here, but play the " If the trade-in won't get at least $3500, we will sell it ourselves first, and then come in for the car" card.
As our DD is getting to a "drivable" age, when we purchased a new car in March, we did not have a trade, we are keeping it for DD. We knew down too the penny exactly what we wanted to spend on the car. Our estimate was off by about $35, since we incorrectly figured state licensing fee.
The dealer had some stupid pinstripes painted on the car, and wanted to add $300 for those...UMM - NO. Not paying for pinstripes that add nothing to the functionality of the car. Our other option was to go to a different dealer, and they had a car for the same price, but instead of the pinstripes, the car had the back-up beepers, which I would have paid the $300 for. We weren't shy about asking for the pinstripe cost to be deducted. Once they realized how serious we were about buying the car, and if it wasn't this car, the next car on our list was at a different dealer, they made it work.
To the OP - Good luck with this!