Think about Athenry/Oranmore/Monivea side of the city when you start looking to buy. Galway city is very very expensive. You will get much more house for your money in Athenry/Oranmore or Monivea, although these area's are getting quite built up now too.
If you want to live in the city initally for the night life etc. try wellpark, college rd, bohermore, woodquay, newcastle rd, lurgan, salthill, rahoon. Avoid Knocknacarra or Cappagh rd area. There are literally thousands of houses up there with poor buses, no shops or pubs and it's just life less.