Yes, both Slack and Textline offer a Free Trial.
Slack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Textline is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Slack Starts at $2.67/Month whereas for Textline Starts at $29.99/Month when Billed Yearly.
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 Textline includes ExpertTexting, TextToHire, SMS Gateway Hub, Senderium, MOBtexting, SimpleTexting, MessageDesk, SendHub and Buddy Texts.