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?
designation used only to detail the trim for the Chevrolet C/K pickup trucks, Suburbans, and Tahoes from 1975 through 1999. GMC used a few variations of the "Sierra" name (e.g. Sierra, Sierra Classic, Sierra Grande, and High Sierra) as both model names and trim lines; however, Chevrolet still uses the CK and the CC in their current model codes.
The Chevrolet Silverado and GMC Sierra trucks have been essentially the same for their entire history. However, there are some trim and add
Chevrolet Silverado
The Chevrolet Silverado, and its mechanically identical cousin the GMC Sierra, are a series of full-size and heavy-duty pickup trucks manufactured by General Motors and introduced in 1998 as the successor to the long-running Chevrolet C/K line. The Silverado name was taken from a trim level previously used on its predecessor, the Chevrolet C/K pickup truck from 1975 through 1998. General Motors continues to offer a GMC-badged variant of the Chevrolet full-size pickup under the GMC Sierra name