What should I charge for postal addresses as an upsell?

I have a business question - hope it's appropriate to put this here (not directly Clay related). I'm talking to a new prospect and they're ready to launch a pretty sizeable email campaign. They asked whether I could also provide with direct-mail addresses. For the DB that I'm using (about 1.4M records), I already have the postal addresses. What should I charge the client for postal addresses? My CPL for cold email with them is going to be between $0.59-$0.20. My thought is to put it at $0.10 per address. Does that make sense?! Easy upsell 🤷🏼‍♂️