And if you create a stack system for sightstone ?

Simple idea:

price 800 => 500 Health 150 => 100 Number ward 3 New passive unique: The ward you destroy you relate 2 times more gold New passive unique: destroy given 1 stack (max 15)

With well over 3 sighstone upgrade possibility in the shop:

Upgrade AP 1 (purple color): 500 gold and 5 stack Number ward 4 150 Health 35 Ability power

Upgrade AP 2: 800 gold (total 1800) and 15 stack Number ward 4 Ward duration 150 => 180 seconds 200 Health 50 Ability power 10% Cooldown reduction

Upgrade AD 1 (orange color): 500 gold and 5 stack Number ward 4 150 Health 20% Attack speed

Upgrade AD 2: 800 gold (total 1800) and 15 stack Number ward 4 Ward duration 150 => 180 seconds 200 Health 30% Attack speed 10% Cooldown reduction

Upgrade Tank 1 (red color): 500 gold and 5 stack Number ward 4 400 Health

Upgrade Tank 2: 800 gold (total 1800) and 15 stack Number ward 4 Ward duration 150 => 180 seconds 600 Health