Google play store commission charge

Physical products are not charged commission, what about services e.g. technical support service or teaching service for computers or even mobile phone - to help user setup/configure/debug issues with their devices. This service already exists and provided by a person remotely - and can also be provided separately w/o App via phone. If we decide to create an App for clients to pay for such services, and schedule or initiate support phone call - will there be any commission charge?

Also, I would like to know Does Google Play Store charge a 30% fee for in-app web view .what if I have a payment gateway e.g Paypal or payment through credit/debit card in the web view. will google still charge me 15–30% fee?