Spam is a major problem, and most governments have brought in laws to crack down on it hard (not before time!) Use a bulk e-mail list, and you will almost certainly end up being reported for spam, with dire consequences.

Further, many if not most of the e-mail addresses on such lists may be duplicates, or out of date (possibly abandoned because of the amount of spam they were receiving.)

Even more, most reputable mailing server providers will not allow you to use such lists, and will promptly shut down your account if you try. After all, if you get busted for sending spam, they and all their other account holders will also suffer.

Bottom line: ignore the ad, and keep your thirty bucks. There are far better, more reliable, more effective – and legal! – ways to build your mailing list.