One major thing you are going to need to look for is experience. How long has this company been selling email lists? You are going to want to look for a company that has had extensive experience and knows how to meet your personal needs for your particular marketing campaign. A safe bet is at least five years experience. Another thing to look for is geographical search options. On the website, you should be able to search for email lists by zip code before you make your purchase. If this option is not available, you are probably going to want to look elsewhere.
A sure way to make certain the email list company is legitimate is by looking up their Better Business Bureau rating. An A rating is what you are looking for here because if you are going to be spending money, you are going to want to make sure you are getting nothing less than excellence. If you are relatively new to this process, I would also suggest calling the actual company so you can speak to knowledgeable sales professional that can guide you through your sale. If you call during their business hours and someone does not answer the phone or you are brought to an automated messaging system; that should immediately tell you that that company is not for you.
One final thing to check for is bounce back guarantees. This will protect you from possibly purchasing an unclean email list. When you buy email address lists, you are going to want to make sure they keep their data clean by rigorously practicing list hygiene. A company that does offer bounce back guarantees is crucial because this will ensure that you are reaching the customers who are most likely going to respond positively to your advertising efforts. Many have found great success using this type of advertising. Political campaign management companies, daily deal companies, and car dealerships all grow propriety off of email address lists because they are able to reach many customers who not only live around their business, but also find their product/service useful and relevant to them.