There is no such thing as "free After Effects for Mac". Oh, wait -- someone can buy AE for Mac and give it to you... then it's free.
There is a tryout version of AE on the Adobe web site. It DOES NOT have the third-party plugins that are bundled with AE when you buy it, like Keylight and all the CC Effects (e.g. CC Sphere, CC Mr. Mercury, etc.
I believe the tryout period is either two weeks or thirty days.
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