I have decided to take the plunge, and offer ADRIFT 5 for free.
There are several reasons for doing this. These include the release of Inform 7, which is easier to use than it's predecessor (although still not a patch on ADRIFT!) and makes it simpler for non-programmers to get started with. Also with Quest becoming free it increases the number of no-pay alternatives, making the decision of which system to use somewhat more difficult. In addition, a large proportion of the ADRIFT user-base are minors who do not have easy access to online payments.
I really think ADRIFT 5 has the potential to become a major player in the IF world - but only at the right price. It is by far the easiest system to use, and has been for some time. Now at least, that ease of use will be open to everyone.
The first free version will be 5.0.19. I don't anticipate this will be ready for release for a good few weeks yet however.