Yes, both Calendly and Customer.io offer a Free Trial.
Calendly is designed for Individuals, Freelancers, Large Enterprises, Medium Business and Small Business.
Customer.io is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Calendly Starts at $8/User/Month when Billed Yearly whereas for Customer.io Starts at $100/Month.
Some top alternatives to Calendly includes Appointy, Acuity Scheduling, Setmore, Microsoft Bookings, Cogsworth, Book Like A Boss, Doodle, Tidycal, Cal.com, DaySchedule, Google Calendar, Calendar and Zoho Booking.
Some top alternatives to Customer.io includes Outgrow, ActiveCampaign, CleverTap, Moosend, Omnisend, ActiveTrail, Iterable, Hubspot Marketing Hub, Klaviyo, SendGrid, MailChimp, StreamSend, Adobe Marketo Engage and Contactspot.