Google Ads Keyword Research & Strategy for a Local Plumbing Business

Hi. I run a small plumbing company in the east end of Toronto. Two vans, me and an apprentice, been going since 2011. Most of our work comes from word of mouth and the vans, and I would like to get some of it coming from Google instead.

We tried Google Ads earlier this year. My nephew set it up for us, nice kid but neither of us knew what we were doing. We put a few hundred dollars in over three weeks and got two phone calls out of it, and neither of them turned into a job. It has been paused since.

Before anybody talks me into running ads again, I want to understand what people around here are actually typing into Google when they need a plumber, and just as importantly what I should not be paying for. Last time we were clearly paying for the wrong people.

What I am looking for:

A keyword list for my services and my area, in a spreadsheet I can keep
The keywords sorted into sensible groups rather than one big pile
A list of words to block, so I stop paying for people who were never going to hire me
A rough idea what a click costs around here, so I know what I am walking into
A short note on how you would set the campaign up and what to spend per day