Yes... make SURE you investigate your options in great depth before jumping at one with your wallet.

I have a friend who deals with lists and mailing to them for an extremely large company in Florida. A vast majority of lists that you'll find will be trash. But there are gems out there, but they come at a cost depending on the volume you seek, and how "clean" the list is.

A bad list will ruin more than your day. Many lists are seeded with spam-cop email addresses who will get you blacklisted everywhere, and the occasional spam fanatic who will make your life miserable. Make sure the list you buy is constantly filtered and cleaned for bad addresses, and matched against known problem lists.

Just my .02