In 1958 a bill that required automobile manufacturers to place a price information sheet on all new vehicles was passed. Senator John Monroney was the one leading the bill. The bill became law in 1958. These information sheets are known as Monroney labels or more commonly known as window stickers, named after the senator. When the manufacturers first stared using the window stickers, they put information about the vehicle on them. This information consisted of options (optional equipment) that was already attached to the vehicle. As time progressed the stickers had not only the optional equipment that was installed, but also the standard features, gas mileage, etc that helped the consumers see the true value of a vehicle.
When selling a vehicle, the sellers look at these stickers to understand the true value being offered by the dealership. If they like the options and features the vehicle comes with, there is a sale to be made there. Depending upon the manufacturer, some features are standard on their vehicles, where as on other manufacturers, the same features are more like options where the buyer has to pay extra to get them on their vehicle.
The price of a vehicle may vary significantly based on the options available in it. A car that costs $30,000 could have about $5000 worth of options installed on it if the sales team and the back office did their job right.