DO NOT PAY for these items. Most of them are available for free from various online sources.
This to me looks like yet another money grab (albeit maybe well intentioned) opportunity by a religious group. Hey you Christians at this outreach!! ever hear "You received free, give free?"
I think that's a bit of an unfair swipe at a ministry that has done a lot of good. When Jesus said you had "received free" and should "give free", he wasn't talking about paper, ink and plastic. He was talking about information that would lead people to come to know him. That we can easily give "free" to anyone we meet. But I see nothing in his words that would prevent anyone from charging a fair price for printed literature or other manufactured media that offered detailed information on specific issues.
The items offered on the web page cited are bound books and videotapes, not just photocopies. Those things cost money and time to develop and produce (and even photocopies cost something to make). A ministry that just gave such things away for free probably wouldn't survive financially. And, the specific information found in those materials is not found anywhere for free on the net, that I've ever seen. One might approximate the information by doing a lot of research, but isn't that one of the main reasons why people write nonfiction books? To gather information on a topic into one place so that it's available without extensive research?
I know the MacGregors - they are fine people, have done a lot of good with their ministry, and have led many people out of cults. They spend much of their time traveling and addressing churches and conferences about cults and destructive groups. The amount of energy thay devote to their ministry would probably have made them quite wealthy, had they chosen to focus it on a secular business, but instead they choose to devote their energies to glorifying the Lord. But a ministry such as theirs has expenses, and they are able to meet these expenses, at least partially, by selling useful materials related to the topics they concern themselves with. I think that's a much healthier way to support a ministry than to constantly be begging for donations.