Vayne costs 4800 ip and is a attack damage carry. Her early level 1-5 game is not very strong but does drastically increase when getting her ult and her first item, which for me is Blade of the Ruin King. With this she now becomes very aggressive and mobile, not as in roaming but as in dodging abilities, for example a niddale spear can be dodged with Vaynes Q which is a roll. Vaynes 4 abilities are: Q- Rolls towards the cursor and gives her a one shot increase in attack damage, W- stacks on the enemy and on the 3rd hit her basic attack does extra damage, E- Pushes the enemy away and stuns them if they are pushed into a wall, R- Gives Vayne a increase in damage and makes her invisible when she rolls(Q).

For building Vayne I would start with a dorans blade and 1 health pot. And then get the Blade of the Ruin King, Berserker Greaves,Infinity Edge, Blood Thirster, Last Whisperer, and either a Phantom Dancer or a Guardian Angel. That is up to you.

For playing Vayne i would play passive until I either finish my Bork(Blade of the Ruin King) or when i get my ultimate. During that time i would farm and get as much gold as possible. Once you finish your build you will have a good amount of attack speed and damage and with the Lase Whisperer you will have Armor penetration, so tanks that have lots of armor will not be a problem.

Enjoy Vayne, she is a very fun champion to be good as.