Yes, both Okta and Slack offer a Free Trial.
Okta is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Slack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Pricing for Okta Starts at $2/User/Month whereas for Slack Starts at $2.67/Month.
Some top alternatives to Okta includes Oracle Identity Management, SailPoint IdentityIQ, WSO2 Identity Server, Keycloak, Azure AD, Ping Intelligent Identity, Ping Identity, Teamstack, Auth0, Frontegg and Login-Master.
Some top alternatives to Slack includes Microsoft Teams, Glip, Google Chat, ChatWork, Dialog, Office Chat, imBee, Takle, SPACE Channel and Teamwork Chat.