Hi as @bananallamas says lists online will tell you you need all kinds of things that you probably don't need. Companies also target worried parents with all kinds of fancy things that are nice but mostly unnecessary. Babies have survived for thousands of years without most of the kit people buy these days. Looking at my own list it includes :
Clothes - including bodysuits (all in one thing) vests, hats, cardigans and a coat or pramsuit. I would go for comfy outfits suitable for sleeping in, I see so many adorable expensive outfits but they look so uncomfortable! Check out ebay, there are usually bundles of clothes for sale. I recently bought 3 bundles for £15 all together and I should have everything I need now except a coat.
Nappies & wipes
Changing mat
Car seat
Pram
Crib/cot
Under "maybe need" on the list are things like :
A Steriliser and bottles
Formula
A moses basket or place for daytime naps (we live in a bungalow so I don't think it's necessary for us but might be worth considering if you want somewhere for baby to nap downstairs) You can pick up pretty cheap ones from most supermarkets or try and find one 2nd hand.
A bouncy/vibrating chair - some babies hate being put down but are soothed by these so you can get stuff done.
Sling/baby carrier - may be helpful if you want to keep baby close or they don't like being put down but you need your hands free
Isofix base - these are pricey but if you're doing a lot of taking baby in and out of the car, trying to get the seat belt fitted can be a nightmare. I may invest in one as I'll be rushing around doing a school run and being able to just clip the seat in and out sounds appealing. But it depends on whether you would find it beneficial.
All of the "maybe" things are items that make life a lot easier but you don't need them. If you plan on exclusively breastfeeding you could manage without a Steriliser and bottles. But it might be nice to have the option incase you want a break now and then. BF can be pretty relentless!
I don't have a baby monitor on my list as like I said we live in a small bungalow so I'll be able to hear baby wherever I am anyway! Many people like one for if baby's asleep upstairs alone. I think basic ones are fairly cheap, there isn't really a need for a fancy one with cameras. But you may not need one if you're going to be regularly checking on baby. And they will be in your bedroom at first anyway.
If you want to save money most things are available 2nd hand on ebay or local Facebook groups. Lock down has messed things up by cancelling all the nearly new sales and charity shops but they may start up again soon.
Many people spend loads on a "changing bag" but any large handbag or rucksack will do the job just fine. You can get thin foldable changing mats from the pound shop which are handy to keep in the bag because not everywhere has great changing facilities.
You will probably find that people will buy you stuff as well so there's no need to go overboard. Unless you want to of course. As you can probably tell, I'm a tight arse and I refuse to spend money if I don't have to!