Was this a CarMax Dealership?, because they tried to hire me on the spot. Peculiar tactic to say the least.
Happened to a friend of mine a few years back who also spent hours negotiating with the dealer. He thought he had really cut the price to the bone and had a great deal. Until a couple of weeks later he found out that there was a factory to dealer incentive that he had not know about, so he had really left about $1K still on the table. After that, he decided that the offering a job bit was just a tactic to make the customer think that he really was getting the best possible deal, when it was just another way for the salesman to manipulate the customer into feeling good about the purchase and to guilting them into not making a big fuss if anything else comes up later on.