The vMaterial Library isn't a 90day trial they just have it located on their downloads page which have the IRay plug in 90 day trials for the various other applications. Same with the MDL Exchange. if you notice at the top the page reads NVIDIA® Iray® Plug-In 90 day Trial **AND ** vMaterial Download.

I cannot find an actual way to BUY VMaterials and to the best of my knowledge they are freely available. All a MDL file is is a text file anyway so not like it couldn't be copied. I will find out for positive though.

aka MCDLabs
also known as Daniel Merrill a grumpy old disabled Jarhead.
checkout my freebies at
https://www.sharecg.com/pf/full_uploads.php?pf_user_name=mcdlabs