Yes, both CircleCI and BrowserStack offer a Free Trial.
CircleCI is designed for Large Enterprises, Medium Business and Small Business.
BrowserStack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
The starting price of CircleCI begins at $39/Month, while pricing details for BrowserStack are unavailable.
Some top alternatives to CircleCI includes Codeship, Semaphore, GitLab, Bamboo, AutoRABIT CI, Buildkite, CloudBees Core, Travis CI, AppVeyor and Bitbucket.
Some top alternatives to BrowserStack includes AppAchhi, Provar, LambdaTest, Sauce Labs, TestingBot, Endtest, Perfecto, BugBug, HeadSpin and AWS Device Farm.