There's always lots of ski gear on sale on ebay, that might be worth a look.
Having said that, depending on when you are going, you might pick up new gear as cheap. Last year when we were skiing in March, some of the group picked up jackets & salopettes for around €80 new in the outdoor shop on Capel Street. You can also get ski wear in Dunnes fairly cheap and Aldi/Lidl also do full ski suits for around €60-€70 but these may be sold out by now.