I agreed with all the answers reasoning why Irvine is more expensive than other cities. It's down to three key words - location, location, location. However, Donna, keep in mind you need not to live in Irvine in order to get all the benefits. You can look into Tustin, Lake Forest, Mission Viejo, Foothill Ranch etc. which are surrounding Irvine. The price could be a little more affordable depending on the location.
Best of luck,
Van Nguyen Gordon
Coldwell Banker Platinum Properties
3500 Barranca Pkwy., suite 100 Irvine 92606