hi there, a very beginner question would like to ask all the pro here.plz...do help me

Basically a company's share flow on market is about 10-30% and the rest is hold by own company management team,
other company/corporation, funds , bank and etc.
My question is.......... the price of a share in market is decide by who?who decide the price for going up or down?
is it the price going up/down simply depend on buyer and seller only?

some more, we know that a company come into market is for raise money,my question is
how a company/corporation raise money after their released IPO?
i mean like during IPO price is RM2,
after that the price raise to RM4, What is their benefit in this raise of the price?
does the raise of price do benefit the company?

sorry for such long question,but i think reli does help for those learner,any pro can do help me to answer those question?
a very very thanks for helping.

woh, your answer delighted me.
tq for answering my question.
so, you mean a company is only able to raise the money during the IPO?