You're an e-commerce operator. You get an email: "Join our membership club and get exclusive vape deals, guaranteed stock, and priority access." Sounds tempting, right? But before you sign anything, think of this as a partnership—not a discount coupon. You're about to tie your business to this supplier.

That means you need to ask the same questions you would of any vendor: Who are they? What exactly are they selling? What happens when something goes wrong?