Okay so this is my personal Zed build that i have been playing around with, Depending how you play him ( if better than me) you should EASILY be able to farm up what you need to get your first 3 items and start running over almost anyone in you way.

Why follow the order?
The static Shiv although may not look much but this item actually helps you out tremendously in 3 main aspects of playing zed. First and mainly it adds ALOT of damage to his Ultimate early and late game. (yes these items actually count towards damage for his ult) Secondly the Attack speed and crit help add quicker damage to the person your using your ult on to help secure the kill. and lastly late game every aspect of this weapon adds to ensuring your kill

Why Revive?
Sometimes you may end up carrying your whole team hard and be the only one with kills or be falling behind and need to get back to the farm, You shouldnt have to rely on ignite to secure the kill anyway expecially late game.

Why Infinity edge before blood thirster?
with just the shiv and the infinity edge you have 45 crit chance almost 1/2 hits will crit with zed so that extra 50% damage REALLY helps finish foes' with ease.

Why a blade of ruined king?
as most "pros" know this item aside from its lifesteal and attack speed which are the 2 main reasons why you use this but the 3rd is for making sure you can hurt Tanks or people with alot of HP

Early Game Tips:
Zed even with out runes early game his E+Q cant hurt you don't really need the W until level 5, Also Try to have you static shiv before level 6 to help push ahead early game. Then from there its a lot of minion pushing and farming Zed can only handle 1 on 1 well early on until he has Static shiv, Infinity Edge, Bloody thirster, and Phantom dancer.