Best cheap restaurant in central Dublin?

Shoukd keep this thread going as a general guide to cheap, good places to eat.

Was in town earlier and went to Hanoi Hanoi at the top of capel st across from the black sheep. Vietnamese place, think its new, had a shared spring roll starter and 2 massive bowls of pho for less than 20 quid between two. If you like your Vietnamese food its probably the best I've had in Dublin, and was some feed for a tenner. Nice decor as well(was the building a hotel before??).

Would definitely return and recommend