I think Maternity wear has come a long way in the past 8 years, since I was pregnant with my first child. There is much wider choice now and many mainstream shops have good maternity ranges.
If you want to pick up some cheap bits, theClothesline.ie has good value maternity wear, new and nearly new.
Asos.com has some great dresses etc on sale, I picked up a maternity dress for a wedding for €17; I will be 28 weeks for the wedding so will get to wear it again.
Nelo Maternity has some nice stuff and Haute Mama do too. I got some fab underwear from both of those and a lovely top & dress from Nelo (gonna wear the dress on TV3 in morning for our Big Toddle as its really soft and comfy and I can move well in it, especially as will be running after my 3 year old!).
New Look and Next also have nice maternity ranges and reasonably priced. Most of the above do sale rails, so have a good browse to see what’s on offer.
Littlewoods has some stuff too and again, they do maternity on sale so you can pick up bargains on there as well.