We just had our teak stairs put in a few weeks ago. We bought it from Staircase Manufacturers in Lacken, New Ross. We are very happy with it. I can't say what it cost exactly because it was included in our builders quote. I do know our builder (he has been at the game for years) always uses them.
We tried getting quotes from Pat Rudkins Joinery in Bagenalstown, Co. Carlow. We rang, posted and emailed them countless times but they never got back to us. I do know however that they make lovely staircases. My brother got his stairs from them 5 years ago.