I am new to the use of flash and am completely confused.
Can I use a Canon or Nikon flash with this camera? will I have full capability of all the features these flashes provide?
Or am I restricted to the sony flashes for this camera?
TTL flashes for Sony are made by Sony and such 3rd parties as Nissin, Metz, Sigma (most of non Sony TTL flashes have old style shoe - you will need an adapter)... if you want cheap TTL flash can do w/o wireless optical TTL then you can get a clone of iCorp/Tumax flash - they are very cheap (but quite limited in functionality).
flashes from Canon or Nikon might work as simple dumb manual flashes if they can fire using only a central pin and central pin fits the contact on new Sony hot shoe...
PS: some really old flashes (from pre digital era) might have unsafe (for digital camera) voltage.