whats it really worth? (79' camaro z28????)

hi, i am new here, but am hoping there are some other 79' owners out there who will see this and be able to relate. my son has found an beautiful 1979 camaro z28 w/ t-tops in fantastic condition, ( i currently have a 93') but i cant seem to find anyway to find out the actual value of it. are there any 1979 owners out there who can offer any words of advice?
would appreciate it soooo much
thanks to all
stacey c.