Let me start by saying this is an entirely legit professional association, so I'm looking for legal solutions only. We are a startup, and have been handed tens of thousands of contacts by other associations in the industry that are obviously not competitors. So, these contacts are not exactly double opt-in from us (some are though), but most likely the individuals would not mind receiving a newsletter once a month from us. Plus, any emails will follow the CAN-SPAM act, by having a way to unsubscribe, listing the company address, etc. A newsletter to a smaller group was sent and revealed a 50% opened rate within 2 days. The question is, how do we get these out to the masses cost-effectively, without being banned due to volume/speed or the list sources not being purely ours. Our host will do it for around $170/month, but do we have a chance of being blacklisted for some reason? Or Aweber is $130/month for 10,000-25,000 subscribers, or MailChimp is $150/month for 10,000-25,000 subscribers. Any suggestions or good advice? Obviously building a 100% double opt-in list of our own is the best, but no one would honestly turn down the opportunity here.