If I instruct in the local school, I get £25/hr tacho, nothing for any groundschool.
If I freelance, I charge £150/day, regardless of how much, or little, flying we do. This seems to me fairer all round, as it incentivises them to maximise the use of my time, and doesn't inventivise me to get as many (expensive to them) flying hours as possible, and rather to do whatever is best for their learning. It's rather less than I get in my day job (I'm firmly a part time pilot), but high enough also that I'm not stealing work from people whose living it is.
This is in England.
G