i got it from my wholesaler, do not deal to much in mustangs what is fair market value?
here is what i know

1988 mustang gt
5.0 v8
5spd
odometer reads 68k
no ac (has ac controls)
no ac compressor
doesnt sound like it has a cam or motor work
convertable top works
front windows work
rear windows do not
interior is pretty clean
paint is faded
has some bodywork on rear by light