What part of the country are you in? For most areas that price is way too high, even if it needed nothing. Also, I think $4600 is too high to fix a camshaft, unless they are doing head gaskets too... or maybe even rebuilding the entire thing. (none of which is needed for a camshaft and lifter job, but you've got it torn down pretty close anyway).

 

You can look at www.statewidelist.com, which will search all of craigslist, in your state, and sort it out by city. So you can see what others are going for in a wide area around you.