Asking common guide in city of milan

Hi I looking to find a proper way how to use bus and tram.

subways is using ticket from the shop before the entrance
I try to take autobus, since It use card to pay, and I have cash only I cannot pay I ride it for free. where can I get the card

You're not paying? I don't think you should write it.

The tickets for subways, trams and buses are all the same. You can buy them at the orange ticket machines in the subway stations. You'll start to love this machines. They last 90 min after the stamping, but just for a single journey on the subway!

For the travel cards. They've a validity of a week, a month or an year. You have to buy them at the ATM Points (ATM is Milan's public transportation company).You can find them in the subway stations of:
Duomo
Centrale
Cadorna (I normally go here, lesser queueing)
Loreto
Garibaldi
Romolo

You can recharge the card in every ticket machine! For other information  I suggest you to check the ATM website in English o Italian: http://www.atm.it/en/Pages/default.aspx

I forgot. You can buy the tickets throughout Milan and its metropolitan area at bars, tobacconists, stationers, newspaper stands.