Pivi, i have no idea on European prices
in Russia, ownership of live military ammo is illegal.
dummy / deactivated SP-5 or SP-6 are worth about 100-300 rub (US $3-$10), depending on the greed of the seller and the conditions of the round (i.e. was the bullet fired or just pulled out and then carefully inserted back after deactivation)
i have some deactivated stuff in my "for trade" bin, but the problem is that the Russian mail is quite unreliable and express carriers (i.e. EMS) will not accept even dummy ammo w/o police certificate saying that the thing is inert and legal to send.