Getting a visa to Tanzania is pretty easy, at least it was for me since I got it at the terrestrial border.  All you need is: 

- A valid passport,

- A valid yellow fever certificate (A MUST TO TRAVEL TO EAST AFRICA)

- 50 USD for visa fees (applies to all nationalities that need a visa except US Citizens for whom the visa costs 100 USD)

 

  It can also be obtained at the embassy prior to the trip or at the airport upon arrival. 

I know it costs more when applying through the embassy and I have no idea for the price at the airport since I took the bus from Nairobi