The right front mount is almost completely removed just to do the TB change, so the additional cost for that should be just the part cost(plus three easy bolts).
The plugs are expensive at the dealer, about $13 each. You can get them for half that at Amazon. The other $110 of that job is labor.
The left rear shock may have failed. Its a relatively easy replacement, though, so you could do it yourself for the cost of the shock. I'd probably do both at the same time.
The TB is not an easy thing to get to and change. It is several hours of labor, and really should include the tensioner and water pump(at least) at the same time. The water pump usually implies a coolant change, but that's not absolutely required. On the other hand, if its time for the first TB change, the coolant is due for a change anyway. Typical charge for the TB job is $700-$900.