I think what you buy really depends on how your house/flat is.
We have a big house, so I had 3 diaper changing station set up, 3 beds (one next to me cot, one in the nursery, and one small cot in the living room).
If you have a smaller space, you will definitely need less.
For a next to me cot, we used Tutti Bambini coZee, which I won't recommend. You can get a much better or the same one for cheaper.
People say babies don't need load, which is true. But you do if you want to keep sane.
I had plenty of Muslims, blankets, breastfeeding pillows, etc. lying around the house and in the ca, so I never had to spend time searching or carrying them with me all the time.
You can always buy things used (except mattress which you usually have to order as an extra - they don't come with the cots, next to me bed etc.)
What I would definitely recommend is to have a baby bouncer (small ones are the best as you can carry them around your home) and a baby carrier so you can have the baby on you - as a first time mother I didn't know that I won't be able to put down my newborn- so these things were life saver to me.