Best Appointment Schedule Plugin for WordPress?

I'm trying to find the best WordPress appointment scheduler plugin for booking appointments online. 

I need something user-friendly for both parties.

Any suggestions?    

Suggest a resource

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Bookly Booking Plugin – Responsive Appointment Booking and Scheduling

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Automated online booking & scheduling for Wordpress: fully customizable booking form with online payments, notifications, and Google Calendar sync. 

Bookly is probably the most popular appointment plugin for WordPress. A little pricey at $60, but it does everything, is often updated, and well supported.