I am almost certain that the way this thing goes is not by stealing credit cards or anything like that, but by using .EDU email address (for students), Malwarebytes give students 4 years for 5$, the 3.75$ is what the OP charges for that promo code, so in other words, you are actually paying $3.75 because you have no access to an EDU email and you don't know what I just told you, without discussing whether that is ethical/legal/worth it or not, I think it's highly unlikely that the license will be terminated because there is no way for them to know you are not a real "student".