@FGol
to know how much free space you have on your root file system, open an xterm and give the df command.
You'll get something like this:

~ $ df
Filesystem 1k-blocks Used Available Use% Mounted on
/dev/mmcblk0p2 2048 2048 0 100% /mnt/initfsnone 512 168 344 33% /mnt/initfs/tmp
/dev/mmcblk1p2 990200 463028 476872 49% /
none 512 168 344 33% /tmp
none 1024 28 996 3% /dev
tmpfs 1024 0 1024 0% /dev/shm
/dev/mmcblk1p1 7969280 4202016 3767264 53% /media/mmc1/dev/mmcblk0p1 958112 401564 556548 42% /media/mmc2

The row you are interested in is the one ending with "/".
Here I have 49% free only because I cloned my root on a 1 GB partition from my internal flash memory.
It's true that installing all those useful programs the 256 MB of the default root file system get quickly consumed.