According to Automotive News, the list is the ongoing project of lawyer Ronald Burdge from Dayton, OH. The dictionary reportedly started about 15 years ago when Burdge obtained it from a dealer's employees as part of a lawsuit. Since then, he's kept it up to date.
The lexicon varies from commonly understood and innocuous terms, including "low ball" and "tire kicker." Beater, iron, sled and toad are all words for a worthless old jalopy.
However, Burdge also lists jargon for some lesser-known and often very unscrupulous acts. For example, the "five-finger close" happens when a sales manager hides a portion of a document with a hand to keep the buyer from noticing that the final numbers aren't as discussed. The move is somewhat related to "sealing the customer," which involves putting signed papers in a sealed or even stapled envelope as a way to hide things from buyers. There's also the "high penny roll" where the finance computers increase payment amounts to a higher number without changing it by a full dollar to keep consumers from catching on.
Not everything is quite so negative, though. For example, most buyers might want to be known as want a "chiseler" – someone who is a hard negotiator. And one of the best terms on the list is a "gold balls" – a person with a high down payment and good credit. The whole dictionary goes into even deeper detail and is definitely worth browsing, even just for a laugh.