Pub is a tradition in Ireland and it's useful to drink a beer with friends on the night. You can even get some Irish food.
You will find different pubs: some are for young people, other for older people or very quiet ambiance.
Sometimes, you can dance in pubs like the Zanzibar and the Mss Miguire or listen to some Irish gigs like in Temple Bar.
There is a popular area for pubs and restaurants: Temple Bar. Have a look of the ambiance on the Saturday night on the street, that's amazing!
To find some Pub in Dublin, look at:
There around 800 Restaurants in Dublin.
Price vary, around 25€ for cheap price.
If you are looking for an online guide with a good short list to eat cheaply in Dublin, you may visit http://www.menupages.ie