E-mail List Sources

I've used the Advanced Search feature to try and find an existing answer to this question, but couldn't find exactly what I was looking for, so here goes:

I know there are lots of companies out there selling lists of email addresses. To my knowledge, there are several types of lists available:

1) mass mailing lists (as in, "get 1 million names for $5" type lists). Essentially worthless.

2) lists of people who have opted in to common areas of interest (for example, gardening) and who don't mind receiving 3rd party offers. Better, but still not what I'm looking for.

3) lists of people who have opted in to common areas of interest, who don't mind receiving 3rd party offers, AND - are proven "buyers of products via the Internet" (not IM products, but other general merchandise).

The 3rd type of list is what I'm looking for; lists of buyers/credit card holders. I know there are some list companies out there that offer this type of list: Jeff Walker referred to one of them in one of his videos. But I'll be darned if I can find it in my notes anywhere.

Can anyone point me in the right direction or suggest one or more good list companies who have this type of list? Thank you very much!