Scrolls can be obtained from the Donation Store for 100 dollars and it equips to the arrow slot. Since it equips to the arrow slot it doesn't use up any slots that are useful.
The Scroll of Souls gives x2 soul drops on all NPC's that drop souls. It's a really good investment if you are a hardcore pvmer.
(Scroll of Souls is tradable.)
The Scroll of blood gives 25% more damage while you're inside of the Theatre of Blood raid and 15% luck while opening the chest at the end.
(Scroll of Blood is tradable)
The scroll of luck gives 5% luck bonus
(Scroll of Luck is untradable)
Scroll of fire works like the Slimer pet where it does 2500 RS3 Damage or 250 OSRS damage every tick.
(Scroll of Fire is tradable)