Tipping Etiquette

I don't know what the proper etiquette is for tipping. I am seeing a provider again after a wonderful experience the first time. I paid her fee the first time the standard way with an envelope when I entered.

Is it proper to pay extra in the envelope upfront or is it better to thank them for a wonderful experience and pull cash out out my pocket as a thank you?

I understand tipping is appreciated but unlike a restaurant where 15-20% is standard, what is appropriate? Is $100 for a provider charging $700 for an hour acceptable?

Not trying to be cheap but the $700 is a lot on my budget but worth the experience. I do want her to know she amazing and I appreciate her time.

Thank you for your input.