If the seal is broken, the product inside could have been exposed to air, moisture, or even worse—someone could have swapped the liquid with something else. You have no idea what you're getting. That's why you should never buy a vape product with a broken seal, even if it's discounted. The risk isn't worth the few dollars you save.

Also, be wary of products that look like they've been sitting on the shelf too long. Check the expiration date. Vape juice degrades over time, and using expired liquid can taste bad and might not work as well.