bhelpuri,
Certain sellers and manufacturers can 'hack' the player so it displays as 1 Gig of storage when seen from Windows Explorer when it actually has 128MB of storage instead. For obvious reasons, 128MB flash memory is cheaper than a 1Gb one.
The best way to know for sure is to FORMAT your player using the MP3 Utilities (which you can download from our site
here). This will wipe it clean and should show u the true storage.
Also, if someone tells you that you can only store 115Mb out of 1 Gig, I would definately question that and how legit the product is. Try filling your player with about 900MB of files and see what happens. It should error if it can't store that much.
Good luck and hope you didn't get ripped off.