I have an opportunity to pick one up with no box. What's the story on these? Are they rare? What should I pay? I know next to nothing on splice and have never even seen one let alone buy one.

Originally they were an exclusive, but I did see them hit OPD's and vaults afterwards. I wouldn't say they are rare, but in the end they're a Splice, so still worthwhile even if they're not flashy. The Rootbeer is the only really common one. Retail was a bit less since they were the only one without Iridium. If you can get them for not too much, I'd certainly jump on them.

What does opd mean?

Oakley Premium Dealer

They were created in response to the falling out with Sunglass Hut. Basically sunglass stores that got the towers and goodies, as well as many of the exclusive colorways.