If you want to have a mess about with one of these Raspberry Pi 2's then you will need the following:
Raspberry Pi 2 from Marlins etc
Micro USB power supply (must be 2 amp, e.g. an old micro USB phone charger)
A TV or monitor with a HDMI input
The Pi 2 comes with the operating system on an 8gig card so you just plug it in and you're away... And add a wifi thing or plug it into your router then you'll have internet too
Loads of fun if you want to put the hours in, but be warned, it can be hard work.
To be continued....