SAGE has an agreement with VSNU Netherlands institutions, which is running between 2017 and 2019. The details of the deal are as follows:
Subscription journals which offer SAGE Choice: The articles of corresponding authors from various VSNU Netherlands institutions can be made open access through SAGE Choice, SAGE's hybrid open access option, free of charge.
Gold open access journals: Corresponding authors publishing an article in a gold open access journal may be entitled to a 20% discount on the prevailing article processing charge (APC) for that journal.
For more information on restrictions and to see how to redeem your VSNU offer, please follow this link and find the SAGE section: http://www.openaccess.nl/en/in-the-netherlands/publisher-deals.