Is it advisable to have two kids or one child is also fine, considering that the kid will have no real sibling?

Personally I feel it is better to have two kids and I do!! The child learns the concept of sharing which is very very important. Also there is company for each other growing up. In today's day and age expenses of raising a child especially from the education point of view has gone up astronomically; so many people are sticking to the concept of 1 child.