Impossible to think that you can buy toothpaste that isn't in a tube. However, there are several plastic free alternatives to toothpaste. First of all, you can make toothpaste by yourself. Secondly, if you can't make your own toothpaste or even if you just don't want to, you can order toothpaste in a jar online. Finally, you can buy toothpaste (and mouthwash) tablets.
Toothpaste Recipe:
https://draxe.com/homemade-baking-soda-toothpaste/