Looks like I missed out on this offer: 100GB Free Google Drive Storage (for 2 years) for Eligible Chromebooks. For some reason, Google is not offering this to Cr-48, Acer AC700, or Samsung Series 5 computers. I think it's strange that this offer would not be extended to older (early adopter) machines. I know that the Cr-48s were given away in the first place and maybe that's one reason they're not being given even more, but I don't think that it would cost Google very much to allow ALL Chromebooks to have the free storage.
The free storage is only for 2 years and I bet that people would continue the subscription for $5/month after that. I'm a little bummed that I don't get the free storage. I've been stoked about my Chromebook and would consider getting another one in the future.
You can read more about the terms and conditions of this offer here.