Is it free?
Waveform is free to use for 30 days, after which a licence will need to be purchased for £29.99 (roughly $38). The licence will entitle you to continue receiving software updates for a one year period. After one year, you will need to re-purchase a licence in order to continue receiving updates, though you can choose not to and continue using the software as-is.
Can I use the software after the 30 day period has run out, and I don't buy a licence?
No, you will need to buy a licence to continue using the software after the 30 day period.
Can I use the software after my bought licence runs out, and I don't purchase another one?
Yes, you purchased a lifetime licence so you can continue using the software forever. However you will not receive any more updates until you purchase a new licence.
Can I use models created in Waveform for commercial purposes?
Yes, it doesn't matter if they were created in the free or paid version, you are free to do what you want with them.
Do I need to give credit?
A link back to waveform3d.com would be appreciated, but not mandatory.
Are there any differences between the free or paid version?
No there is no difference. The free version contains all the features, so you can fully try it out during the trial period.
How many people to a licence?
It is one licence per person (or per work station). A company would need to purchase a licence for each of its employees.