There are lots of budget hotels often located on the outskirts of cities who cater to business people during the week and offer great rates to families at the weekend. Many of these are included in Supervalu Breaks which offer 2 nights accommodation including breakfast and one evening meal for just €99 per person, two children under 10 sleeping in the same room go free, with a completed 50 token card(you get one for every €10 you spend in Supervalu. This is obviously a great option if you have kids especially if the hotel has a kids club and or leisure centre and swimming pool.
The same or even better offers apply midweek which are geared to retired people often with a third nights accommodation free. Of course they are hoping you will spend some money too but for a lot of budget hotels around the country it's at least keeping the lights on. The only downside of these breaks is that they are obviously geared to appeal to other young families so unless you have buckets of patience, or you are a little bit deaf, don’t mind falling over buggies in the lobby or having unruly kids run riot in the diningroom stay clear....