Hello @JeffreyH977 ,
For legal and Compliance reasons, you need to have permission from the contacts to be emailing them. Based on that, there's a very, very limited scope of when you'd be allowed to email a third party's contacts. Purchased lists are absolutely not allowed. Contacts from an org you're a member of will vary greatly based on the context. I'd definitely recommend reviewing our Email Permission Policy to make sure you're understanding what contacts you can email, and if you have further questions I'd recommend reaching out to the Review team.