First, let’s review the distinction between buying lists and renting lists.
Renting a list means you pay a sponsorship-type fee to a third party for the right to send a set number of emails to their opted-in subscribers. These subscribers have let the vendor know that they are open to receiving relevant offers from the vendor’s network of partners. Typically, you will provide creative to the vendor and the actual list of email addresses will never be in your hands. You can, of course, then drive the recipients to a landing page where they can convert and become prospects in your system as a part of your house list. This is an acceptable marketing tactic.
Buying a list means that you’ve paid a one-time fee to receive an actual, physical list of people’s email addresses. This would be a list that you could import in to your system and use as many times as you want, just as you would an organically developed house list.
So what’s wrong with buying a list?
When it boils down to it, the people on that list did not opt-in to receiving your communication. They also did not give permission to receive email from a trusted partner, as in the case of the third-party list rental. When you don’t know where the names came from, you run a much higher risk of being reported as a spammer by the recipients. This can permanently damage your sender reputation and hurt your delieverablilty for years to come. Another thing to keep in mind is that these lists are not typically well maintained. It may look like a great value to purchase thousands of email addresses for a low fee, but the “value” is cut in half when you have a 50% bounce rate.
The bottom line is stay away from purchased lists. If it seems too easy, it probably is. Consider the long term repercussions rather than the short term appeal.