Perhaps the biggest email mistake you can make is to purchase an email list. At least a few times every week I get an email asking where to buy an email list. I always respond with the same thing… “don’t”.
An email list that you build organically is ALWAYS going to perform better than a list you buy. First of all, the bought lists tend to have incomplete data or are out-of-date. Or even worse, you could buy email addresses that were harvested from the web.
Also, other people will be using the list, just like you. They’ll be sending out emails to the same recipients. Chances are that the people on your bought list are already annoyed with the emails they’re getting, so you sending some more isn’t going to help.
Plus, you could run into trouble with your email service provider. If too many of your messages get marked as spam (because you’re sending unsolicited email) your account could be banned.
Take my advice and build your list organically. I currently use OptinMonster to collect email addresses and build my list.