Time is money.
Time, not raw material and labour cost, constitutes the biggest portion of the overall cost in many jobs.
Is the price you are charged to have something done for you the actual or overall cost to you?
Is the price cheap just because it is lower-priced ?
Is it expensive just because it is higher-priced?
How much time he takes to do it for you is one thing.
How much time it involves you directly and indirectly is another thing.