The Mp5a5 there costed around $300 or so shipped.
THe berreta on the bottom costed $120 or so. The berreta is a Gas Blow back meaning it uses gas as propellant and the slide actually slides back here is a animation

On knowing when your hit:
Basically this is a honor sport. Yes you can be a butt head
and not call yourself out. But wen you shoot a guy with a 400 fps
airsoft gun and he gets hit and screams and doesnt call himself out,
you know hes cheating.BUT TRUST ME! YOU KNOW WHEN YOUR HIT...unless thers sometimes were you get hit and you dont know it.