Samsung Galaxy Grand is running out of space I'm using a Samsung Galaxy Grand and I have not much apps installed: in fact just about 3 apps besides the pre-installed apps, but still I have no space when I'm downloading apps like Skype and Candy Crush. 

On the process of updating my phone I get this message, that there is an insufficient space; the phone too shows a lot of used up space. I have an 8GB microSD card, which is hardly used. 

Please help me on this.
You can clean junk data from mobile:

Clear App Data

Some apps store a lot of temporary files on the internal memory which can build up over time.  Apps like Facebook, Google Maps and web browsers are particularly bad for this, due to the massive amounts of data they have to manage on a regular basis. Clearing out these temporary files can free up a great deal of memory for your smartphone and can be done by following these simple steps:

Go to Settings

Select 'Applications'

Select 'Manage Applications'

Find the application you wish to clear and press on it

Press the options for both 'Clear Data' and 'Clear Cache'

Another simple way to free up storage space is by deleting all the log files in the device memory.

Just dial *#9900# on the tablet and 

select option 2 “Delete dumpstate/logcat” in the prompted menu. 

Hope it helps you!!