The market price is the current amount the stock is selling at on the New York Stock Exchange, the AMEX or any other global exchange.
yes
An example of a ceiling would be rent controlled apartments. A floor would be minimum wage.
There are several definitions of market price depending on on usage. It can be the price of a commodity or share on the stock market. It can also be the best guess of a marketing agent as to what...
It is the price at which demand equals supply, so that the market "clears", i.e. all the goods supplied find a buyer.