That’s going to be tough to be specific on. What else can they do? Is their ability just from training or do they have on the job experience? If so how much? Do they have their own tools, computer, transportation?
If this is a recent high school graduate who got the training and now wants a job, I would offer $10-$15 an hour (maybe less). If this is someone with more than 10 years in the industry and is fully equipped AND brings business + customers, well that will look more like base + commission w/ base possibly being in the range of $20 per hour.
It also depends on the market and the company hiring. A one man operation will be much less than a larger company with employees and office space.