cheapest way or getting from Ireland to Valencia, spain in July

You could use www.clickair.com to get to Barcelona and rent a car to take you down to Valencia. Flights would be around 400 return for 2 adults and 2 children. Car rental for a week would probably work out at about 200 with this crowd: www.pepecar.com.
You could also bus it or train it down from BCN although you'd have to make a few different changes to get there and may not be the easiest depending on the age of your kids etc.
 
thanks for that very interesting information - do you know anything about clickair? Have you ever flown with them?
 
Have you ever flown with them?

Nope, I'm afraid I haven't had the chance to try them out yet. They've only been running for a few months now. Their routes to Ireland haven't even started yet (I think they'll start doing DUB-BCN at the beginning of March).

Edit: They're partly owned by Iberia so I'd suspect that they should be reputable enough.
 
just had a quick look at them and say if you went out 8/7 back 22/7 the grand total would be 440! you could also fly to london heathrow with aer lingus and then use clickair direct to valencia but straight to barcelona would be your best bet.
 
Olivia,

Aer Lingus flew direct last year but only for a limited time - I think it was April to October. You could ring Aer Lingus and see if they plan to run it again this year.
 
I fly to Valencia 3 to 4 times a year. And you have lots of options. My father usually flies to Alicante and takes the bus at the airport. It is really handy and cheap. We also find that hiring a car in Alicante is cheaper than in Valencia and you have the A7 motorway (again just by the airport) that brings you straight to Valencia (it takes about 1 hour and there are 2 stops in Valencia). From Barcelona, you can fly with Vueling.com for €10 each way or Spanair for €25 each way (per adult). Are you staying in the city itself?