Whatever you choose, there are a few non-negotiables.

• Verify the supplier. Check they're licensed to sell vape products in your region. Ask for references from other retailers.
• Request batch test results. This is your safety net. If a customer has a reaction, you want to prove the product was what the manufacturer claimed.
• Check battery safety. For any device with a lithium-ion battery, ask if the battery is certified to relevant safety standards. This matters for shipping and for your customers' safety.
• Have a returns policy. Batteries fail, pods leak. Decide in advance how you'll handle defective units so you don't eat the loss alone.

And don't forget the legal side. Vape products are heavily regulated in the US. Make sure the products you buy comply with FDA rules, and that your sales channels are age-verified. Ignorance isn't a defense.