Yes, both Slack and Aircall offer a Free Trial.
Slack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Aircall is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Pricing for Slack Starts at $2.67/Month whereas for Aircall Starts at $30/User/Month.
Some top alternatives to Slack includes Microsoft Teams, Glip, Google Chat, ChatWork, Dialog, Office Chat, imBee, Takle, SPACE Channel and Teamwork Chat.
Some top alternatives to Aircall includes Novanet Cloud Contact Center, CloudTalk, HoduCC, Call Center Studio, Dialpad Contact Center, 3CX, Vonage Contact Center and RingCentral Contact Center.