An eBay authentication issue cost me a completed sale — and exposed a hole in my shipping process. Here’s what happened, what I misunderstood about the authentication process, and the simple step I’ll take with every valuable raw card going forward.

How do you price a sports card when there are no direct comps? I recently had to figure that out with a true 1/1—and then decide whether to push for more or take the offer in front of me.