The program is free and they have offered many other sister-programs for free, since I have been with them. To date, I have over 1875 "free items", in my collection, directly from Daz3D, in the store. There is another couple thousand items that I have gotten online, legally, for free, from other sources. Daz3D opens them and renders them fine.
Honestly, no other program I have ever used for rendering has been this easy to use and looked this great and realistic, out of the box. For "paid content", it is top of the line stuff that is available, right along items that are just a few notches above the bottom line. The number of professional items is growing fast, quickly pushing out all the older content.
However, don't let the high prices fool you. That is like looking at a cars sticker price. Few actually pay that price. Most things in the Daz store often go on sale for 40-80% off. More often if you are a platinum member. However, to date, using only the free items, I have already done so much. (You honestly only need a hand-full of paid items to have millions of decent variations available to you, with little effort. With the free items, you have the same amount of variation too, but a little less control with the morphs and skins.)
Yes, this can be used for schools, offices or just for fun, as a hobby, without spending a penny. It can even be used professionally, to make renderings that will make you look like an actual professional, even when you are not. (I know, I do it all the time.)
Just be patient if things don't go as planned and take a moment to ask for help, as clearly and calmly and as civil as possible. You WILL get fast responses and solutions, to most issues in the live forums. (The help tickets are more for alerting them of technical issues with the software, not for one-on-one personal help with "learning curves".)