While I search for the magento module in google, I noticed the price is displayed in google search. Can we display the price of the product in google search by using any tag or any other way. Someone tell me what method is used in this.
Magento makes use of hProduct microformat, and that is read by google.
But obviously you don't need to use Magento in order to get google index your product prices. Take a look at google microformat description page:
Be aware though that it might take a while for google to index microformat correctly. Best thing to do if you want to accelerate the process is to use this microformat in multiple locations around the website. Still though in some of my websites it took over a month after initial indexing till I could actually see my product prices on google.