Adobe Flex Builder 3 Pro is available for free to all education customers. This includes all students, faculty and staff of eligible education institutions.

Proof of Eligibility
To receive the product, you must upload a valid proof of eligibility to get the serial numbers to activate the product. Valid proofs of eligibility are:
1. a student ID showing current enrollment,
2. a Faculty ID showing current employment
3. an employee ID showing current employment, or
4. a letter on an educational institution letterhead stating that you are either a current student, a current faculty member or a current employee of the institution.

Terms and conditions
The education version is only available to education customers and is not meant for distribution to institutions, organizations or people outside the authorized educational institution. For additional information on eligibility, please refer to the FAQ.

The Link:

https://freeriatools.adobe.com/flex/?sdid=DXAID

Related Posts:

1. How to Install Adobe Flash Plugin for Google Chrome