Yes, some of them have limited usage, some require from me to register on external service, and to include code…
What I found ‘best’ solution so far is https://appointzilla.com/
Ok, i doesent have the prettiest styling IMHO, but it does the job.
Only one thing – when you add new appointment through the admin area, in one step it asks you to insert customer email, and customer recieves appointment confirmation.. I don’t need it, and I would like to know how to disable it