Yes, both CircleCI and AppVeyor offer a Free Trial.
CircleCI is designed for Large Enterprises, Medium Business and Small Business.
AppVeyor is designed for Large Enterprises, Medium Business and Small Business.
Pricing for CircleCI Starts at $39/Month whereas for AppVeyor Starts at $29.
Some top alternatives to CircleCI includes Codeship, Semaphore, GitLab, Bamboo, AutoRABIT CI, Buildkite, CloudBees Core, Travis CI, AppVeyor and Bitbucket.
Some top alternatives to AppVeyor includes Codeship, Semaphore, GitLab, CircleCI, Bamboo, Buildkite, Travis CI, Razorops and GitlabRunner.