To be fair, Opt Intelligence is more of a service than a tool. They help you generate leads for many different niches. First you have to sign up with them, and then tell them what niche, demographic, location, etc that you need leads from and they'll work with you to come up with a plan, as well as give you concrete per-lead pricing. It's possible to get very cheap leads with Opt Intelligence, and we've had very good success with them.
WARNING: It can take a LONG time to get approved with Opt Intelligence. When we signed up with them it took nearly 3 weeks to get final approval to join. They have been overwhelmed with new customers and are trying to catch up from what we've been told!