The title of the thread is wrong. Your problem may be the cylinder head gasket and definitely not the valve cover. For the replacement of vcg, if you go for a head gasket replacement, the vcg will be included in the kit.
I'm also searching for prices to have "my" head gasket replaced. Run a compression test, first "dry" then "wet", like I did and keep the results. With this you may have a clue of what's inside the motor. Dry for the cylinder head and wet for the block, roughly.
Also, I've been searching for head gasket replacement and it can be DIY, although it must be performed conscientiously, with method and time. Expect some specific tools for the job. First, gather as much info as you can.
And definitely troubleshoot for head gasket failure: smoke, coolant smell, dipstick, creamy oil, bubbles on the expansion tank, too much pressure on cooling hoses, and so on. Donīt really believe in just one symptom. I really believe one problem as more than one clue. At least two clues for the problem. It's pretty well engineered and engineers don't like to make fast judgements.
Keep posting and best regards