Yes, both CircleLoop and Zendesk Talk offer a Free Trial.
CircleLoop is designed for Freelancers, Medium Business and Small Business.
Zendesk Talk is designed for Individuals, Large Enterprises, Medium Business and Small Business.
Pricing for CircleLoop Starts at $6.45/User/Month whereas for Zendesk Talk Starts at $9/User/Month.
Some top alternatives to CircleLoop includes Nextiva, Dialer360, CloudTalk, HoduCC, Call Center Studio, TelebuHub, Truly, 3CX, My Hotline and CloudCall.
Some top alternatives to Zendesk Talk includes Nextiva, TalkDesk, uContact, HoduCC, Call Center Studio, TelebuHub, Zendesk Support, VoxDesk, Zendesk Chat and Freshdesk Contact Center (Formerly Freshcaller).