Some Stuff To Remember
# Skills and Items are differentiated into four categories according to their usefulness or rarity.
Skills/Items:
Common Skills/Items
Uncommon Skills/Items
Rare Skills/Items
Legendary Skills/Items
# Lottery tickets are differentiated into four grades.
Common-grade ticket: Chance to obtain random common skills/items
Uncommon-grade ticket: Chance to obtain random uncommon skills/items
Rare-grade ticket: Chance to obtain random rare skills/items
Legendary-grade ticket: Chance to obtain random legendary skills/items
#Price of tickets:
Common-grade ticket: 100 System Points (SP)
Uncommon-grade ticket: 1,000 System Points (SP)
Rare-grade ticket: 10,000 System Points (SP)
Legendary-grade ticket: 100,000 System Points (SP)
#Recycle Price:
Common skill book/items: 0-999 System Points (SP)
Uncommon skill book/items: 1,000-9,999 System Points (SP)
Rare skill book/items: 10,000-99,999 System Points (SP)
Legendary skill book/items: 100,000+ System Points (SP)
Note: Items/Skills bought from the system can't be recycled to prevent the user from misusing it.
CREATORS' THOUGHTS 
Xumit
Xumit I'm still thinking about the inner working of the system. So, I may add some more stuff here.
Weekly Power Status
-- Power
Ranking 
-- Power
stone