Do the job once, for a real person, before you charge anyone full price.
Free or cheap, for a neighbour, a friend, someone at church. Not for your own household — it has to be someone who will tell you the truth and whose job you cannot leave half-finished.
You cannot price a job you have never done. Everyone guesses low. You think the cleaning takes two hours; it takes four and you used twice the supplies. If you had set your price first, you would have locked yourself into working for six dollars an hour and you would not have found out for a month.
Do it once, with a clock running, and then set the price from what actually happened.
Time yourself. Start to finish, including setup and cleanup. Write the number down that day, not later from memory.
Write down what you used. Every bag, every bottle, every part, and the gas to get there.
Notice what went wrong. The thing you forgot. The step that took three times as long as expected. That is your real cost.
Two things, and you have to ask for both out loud:
Then ask the hard one: "What should I have done differently?" Stay quiet through the whole answer. Do not explain. This is the most valuable minute of the whole job.
Tell the coach how long it really took, what you used, and what they said. That is what turns into your price and your first bit of proof.