[Transformers series] How well off are the human protagonists in Transformers?

Sari from Animated should be loaded with cash, given that she's the adopted scion of a tech company CEO and Spike Witwicky from G1 should fall within lower middle class given his father works at an oil rig.

And speaking about how this ties into robots in disguise thing that Transformers has. Given Sam Witwicky from the Michael Bay movies is a high school student from a middle class family . Sure, a beat up second hand car (which Bumblebee disguised as) would not attract much attention to Sam, but a concept (at the time Transformers was aired) Camaro will attract more attention since people will be wondering how Sam brought the car with his income and draw more attention to Bumblebee.

So, how well off are the human protagonists in Transformers that no one bats an eye at how expensive that new sports car they suddenly have is?

*There's a reason why anti-corruption investigators tend to look at cars.