Welcome to the site, you found a great place to exchnage notes and idea's.
There's no rule prohibiting discussion of money, but I might warn that we are from all over the country.
You might get an idea of a price from me on replacing a water heater, but lose your shirt trying to get that price in your area because the cost of living & overhead are higher where I am.
I use flat rates for the most part.
There are numerous publications that have set rates, but in the end I made my own list based on what my expenses are and how long each task takes me.
Others here use T&M, it all boils down to what you're comfortable with.