FTM...what do I need to buy&when?!

Hey ladies,
​I'm a ftm, still early days (just 9 weeks tomorrow!) but I want to start getting organised and writing lists! 
​So my question is this: what do I need to buy and when should I be buying it?! I don't want to buy anything till in hit 16 weeks at the earliest, but it can't help to plan! 
​Thank you! :)