65 bucks is a bargain - I probably would have asked him to replace the remaining plugs. :)

As a later poster suggested, run the engine to temperature to make extraction easier. I would add that you shuld only loosen the plugs about a quarter turn, then let the engine cool down before removing them - less chance of cross threading with a cold head.

Also, run an old plug coated with motor oil slowly up and down the spark plug holes to clean out and lubricate the threads. The oiled holes should make it easier to thread down to the seat by hand, or with very light pressure on your wrench.

Then use anti seize on the final installation to make the next change easier.