In my part of the world, around $4000 is about right in terms of price.
However, personally, I’d be subtracting something for the possible struts, timing chain, and head gasket repairs. Timing chains generally last the life of the engine; what makes you think it needs to be replaced? Or do you mean timing belt?
And why do you suspect the head gasket is about to fail?
I’d have a mechanic check it over before buying it, and then go from there. It would concern me that you already know about some pretty expensive repair items.