You can also get Amazon Prime with a free
"mom" membership. And its terms & conditions are pretty permissive:
Despite the name, you don't need to be a mom to join. Amazon Mom is open to anyone expecting a baby or caring for a baby or young child, whether you're a mom, dad, grandparent, or caretaker. We just thought "Amazon Primary Caretaker" didn’t have the same ring to it.
They give membership extensions when you make qualified purchases. If you have a young relative, you'll find that many gifts qualify for membership extensions, as do some odd things. Last I remember, I got an extension for buying dishtowels. Go figure. But I've since upgraded to paid Amazon Prime. One free Kindle book a month + streaming movies & TV shows tipped the scales.