i live and work in irvine.. great place to live.. clean safe lots of asian food (if you like that) plenty of parks shopping centers and nice housing. Only downside is night life in Irvine blows! no real bars or places to party. Luckily, there are plenty of places within a 20 mile radius. Huntington Beach, Newport Beach, Fullerton and LA/SD about and hour or so in both directions.
Rent.. i would say 600 - 1000+ for a room depending where you want to live. i pay 800 a month for a master bedroom in a 3 bedroom townhouse. if you get a 1 bedroom spot 1000+
hope that helps a bit. Feel free to PM me if you have any additional questions