How much should a homepage mockup cost from a decent graphic designer? Im talking just the layout in Photoshop and no coding. I received a quote for 800$ and thought that was a bit high.
There’s no way to codify this based on your query. It depends on the amount of time and effort, and expertise, the graphic designer puts into the job. $800 could be quite reasonable (or not), depending.
It is difficult to generalize on how much it should cost. It will vary on how detailed the design is going to be, how much guidance was provided to start and how good the designer is. As it was stated, $800 could be high or actually cheap depending on what your needs are.
On a side note, I think many people have an assumption that the initial mock-up stage is a quick and easy one. In actuality, this step in the process is the most important and requires a lot more work up front. When you are creating the mock-up for the site, you aren’t merely creating the look for the site, you are also planning out the navigation and flow of the entire website. This takes more thought than just throwing a navigation bar across the top (for most sites). Same goes for the design itself.
A good designer will usually take less time converting the design over to a template than to come up with the mock-up, since the code to do so was probably already in their thought process when designing.
So, just something to think about when getting quotes on this stage of the process. 
Look at it this way – is $800 really that much for establishing the look and feel for the entire site? You can’t look at it as “one page” that one page is the key to the rest of the sites appearance. Of course, saying the work quality granted the price tag in the first place.
What they said.