A:AnswerAbout 4.8gb is used with the System.
I found it filled quite quickly with apps.
You need to get SD card best 32Gb. The good news is that about 25 of the apps including heavy ones like Facebook can be moved to the SD after install. On many phone the SD is only for data - in this phone a few apps can move.
A:AnswerThe amount of RAM needed depends on tasks that are required of the phone. If you are a general user then 1 GB should be plenty. If you use a lot of apps then 2 GB would be better.