I know that there are often free premium codes for Grammarly around, but if you miss them or if they do not work, you'll need a workaround.
This method is based on Grammarly's referral system. If you invite a friend and he installs the browser extension, both of you get one week of premium for free. If you invite two friends, the weeks accumulate and you get a week two times, therefore two weeks. Easy as that.
What you have to do:
If you're logged in at Grammarly's homepage,…