Neither Standard Library nor Postman offers a free trial.
Standard Library is designed for Individuals, Freelancers, Medium Business and Small Business.
Postman is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Standard Library Starts at $15/Month whereas for Postman Starts at $12/User/Month when Billed Yearly.
Some top alternatives to Standard Library includes ApiWay, LinkApi, Meta API, API Maker, Codeless, Code2, NoCodeAPI, Merge, ApiX-Drive and Base API.
Some top alternatives to Postman includes Apigee Edge, WSO2 API Manager, SwaggerHub, API Fortress, BlazeMeter, TestMace, Insomnia CLI, Meta API, RestCase and Dapi.