Y need for other applications to save data.... Just download Greenify and stop any applications... Simple bro :)
a free VPN connection and data saving sounds pretty damn good to me.
Will the VPN be the same as the VPN service you'd purchase monthly?
I'm a big fan of opera max but i'll try my best to avoid every apps made by Samsung because they are sucks at optimization i'm pretty sure it will slow down my phone and drain my phone battery significantly