For my first, we used a secondhand next to me crib, secondhand moses basket and secondhand cot (bought all new mattresses, though). I used a lot of secondhand bedding and sleeping bags, too.
We bought a secondhand travel system (I had researched beforehand and was looking for a particular model, this is well worth doing).
We were given a secondhand bouncer.
We were given lots of hand me downs (clothes, toys, etc) and I bought lots of things off FB marketplace.
We were also given lots of clothes, toys, etc. as gifts.
I'm using the same things for my second baby.
The only things you really shouldn't consider buying secondhand are car seats and mattresses. Having said that, I did use a car seat that a family member gave me as I had the instructions for safe use and trusted 100% that it had never been in a crash.
The only other issue with buying secondhand that I can think of would be making sure that items come from a smoke free home.
In essence: buying secondhand is a wise decision and you'll save loads of money. I highly recommend it.
Aside from the issue of 'secondhand', I would add that PPs are right to advise waiting and seeing what you need. Babies are so different. E.g. I was advised to buy loads of dribble bibs and muslins but I probably needed a quarter of what I bought. Aside from buying the contents of your hospital bag, a car seat, a safe place for baby to sleep and a pram, you can wait and see before buying everything else. It's very easy to obtain things quickly these days, so you can use that to your advantage. On the other hand, if buying secondhand, you could always buy things and then re-list if you find something isn't working for you!