SimLab Composer has three editions, and is supported on Windows 32-64bit, and Mac.

Educational licenses are available only for K-12, university students, and teaching faculty. A proof of enrolment, or the use of a reputable *.edu email address is needed to verify eligibility for an educational license.
Unlike commercial licenses educational licenses expire after 24 months.
Educational licenses can NOT be used commercially, and they will be sent only after verifying the buyer status