While I wouldn't advise ANYONE to stock up on DVD-R media, it will not be $0.50 by next year.
If you remember the way CD-R's went - it took quite some time for them to go from $5 each to $0.50 each. Granted - there are some different factors in play now (more people have PCs, more people know how to burn stuff). The difference here - it's still not easy (or legal or possible, to many) for most end-users to burn copies of their DVDs or home movies to DVD. When CD-R got popular, it was because any end user could pop in a CD and make a quick copy of it, with the push of a button.
Given it's first gen equipment and media - I'm hoping to see the media reach $2 or less by the end of the year. The question is - when are next gen drives going to be available, and will they be out for any cheaper than they are now? Or will next gen drives follow the CD-RW path, and be more expensive because of newer features?