I’m having the valve cover gasket replaced on a Z1000 and I was quoted about 150 for the parts, including valve cover gasket, plugs, additional gaskets For the valves (or plugs?) and replacement bolts. Does that sound reasonable?
Have a look through here, make a list of the parts, and see if the price comes up close. Keep in mind that they'll also be using some sealants during the job, that will be on top of the apparent parts cost.