Not sure if this is common knowledge or not, but today I registered my Galaxy S5, and suddenly I now have an extra 48 GB. After a bit of Googling, it seems that most Samsung phones and tablets come with 48 GB of extra Dropbox storage for 24 months, as long as it was pre-loaded with Dropbox. Only eligible for the first user to log-in to the device. (Didn't think it was a "deal", so just posted here in forums)
Select Samsung devices are eligible to receive 48 GB for two years, including:
Devices launched after Fall 2014 with the Dropbox app pre-loaded
Devices launched between 2012 and 2014 that have the Dropbox app pre-loaded with the "out-of-box" experience
Select Samsung devices launched between 2012 and 2014 that have the Dropbox app pre-loaded but do not have the "out-of-box experience" are eligible to receive 48 GB for one year.
Yep I have this too, although I signed up using a friend's phone (they don't use dropbox) because I didn't have a Samsung phone at the time.