Your best bet is to develop a network of people that will serve to send you "referrals" not leads. One of the best ways I have found is working with a regular networking group such as BNI (Business Network International). See if there is a local chapter in your area--you should be able to google it. If there isn't one, start one. The group meets once a week for one and a half hours and can only include one from each person from each industry, i.e. one mortgage broker, one life agent, one p&c agent, one group health & benefits agent, one commercial real estate agent, one residential real estate agent, one commercial furniture sales person, one accountant, one attorney, etc. We get to know each other and each other's business and we pass around qualified referrals--people who are truly interested in you not just a lead which many times can be almost the same as a cold call. I also belong to about four other networking groups that meet at least once or twice a month. Also consider a formal referral program with your existing clients.
The other suggestion is to get connected with a few P & C agents sometimes they are looking for life agents that are willing to sell for their major companies and will give you their clients as long as you sell their products.
I have never found that purchasing leads work for me. My best clients have been referrals whether through my direct networking, a few key referral sources that I have or satisfied clients.