Extremities have a Goretex pair for less than £30, and boy are they high quality items.
My friend who is a recent convert to walking, bought a pair in Bettws Y Coed.
The Extremities cost him £25, and looked bullet proof in manufacture, so well made, that i recon they would last for many years.
If you do need gaiters, then their worth a look, and will not blow the bank.