Good luck finding a brand new one. Through a custom order perhaps. But most you'll find are in the classifieds. They vary from being relitively cheap to very very expensive with ugprades.
I strongly reccomend NOT getting a sniper rifle. At all.
And even moreso for the PSG, you will spend a fortune just to get the thing shooting well.
Get an AEG when you get age verified and attend some scrims rather than assuming what you will be comfortable with. Sniping is not as glorified as video games and movies make it.