I drive a Chevrolet Silverado
That's so cool.  This is  a series of full-size and heavy-duty pickup trucks manufactured by General Motors and introduced in 1998 
What's the likely cost of the car?
Well, just like the price of every average truck out there. The name was  taken from a trim level previously used on its predecessor, the Chevrolet C/K pickup truck from 1975 through 1998.
When was te first commercial production?
I guess in 1987 since the name was first used at that time for GMT400 platform trucks produced by GMC
Who is the CEO ?
To be honest, im not sure. Also, the name Sierra have been used for different variants of GM vehicles  some of these are  Sierra Classic, and High Sierra
Do they have any other car brands?
Of course they do. Another thing is that The Chevrolet Silverado and GMC Sierra trucks have not changed name since their start