Baby supplies- what can I buy?

Re
First time mom here! I'm a planner and am very money conscious. I am a little over 7 weeks and just purchased my first two packs of diapers. I would like to know from the mommies out there what should I start stocking up on? And what do I hold off on for people to most like buy for shower, gifts, etc?
And is there anything that I should wait to buy because of early expiration, etc?