Which alphabet letter is a question?

There is a shop where written:
Buy 1 for $1
10 for $2
100 for $3
I needed 999 and still only paid $3. How could this be financially viable for the shop-keeper?

A person was found dead on a big green land with no trees or buildings around. When the police arrived, they found a piece of rock lying next to him and the man was wearing clothes comprising of red, blue and yellow colours.

Can you tell who the person is and what was the cause of death?

Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

Who has married many women but was never married?

How can you leave a room with two legs and return with six legs?

A man was just doing his job when his suit was torn. Why did he die three minutes later?

Can you identify the hidden rebus in the image below?

The host of a game show, offers the guest a choice of three doors. Behind one is a expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?