A lot of the stuff I had for my son was given to me as gifts. A swing, a stationary play seat with tons of toys on it, bathtub …some of those things consider not necessary. I honestly didn’t use the swing that much. I bought a nice bouncy seat at a garage sale for 75 cents and so I used that quite often when the baby was small and I needed to shower or do up the dishes real fast. Honestly, I held my son a lot when he was newborn, it was fun and enjoyable. Here are some things to me that was worth it, I know these can be quite subjective.
The bouncy seat. For 75 cents, yes. I wouldn’t have spent 50 dollars on one though.
Monitor- This was good for piece of mind as a first time mom. It was a gift though, I didn’t buy it. I still use it, we have a two story house and I especially like it for at night/evening time when I’m downstairs cleaning and he is in bed. Our house is hard to hear in from room to room.
stroller- I used mine a lot, I got the travel set where the carrier snaps onto the strollers. It was awesome for grocery shopping when hubby and I did it together. Next baby we have I will invest in a sling/carrier of some type. I never spent the money on it and didn’t get one as a gift, but I think it would be useful, especially since I’ll have an older child and need free hands a lot. I also took walks every day with my son in the summer time. That was soooo nice when I needed to get out and he was a little older and wanted to sit up like a big boy and look around and play with toys. Slings won’t work then. 
I actually liked the baby bathtub I got. It fit across our sink and was a lot easier on the back. When my son got to be about 5 months or so, he splashed to much and I used it in the tub, which is great for when they can’t sit up. Once he got to be about 9 months, we put away the bathtub for next baby and just let him bathe with us or I plop him in the tub and sit by him and do quick baths. It can be hard on my back(I have scoliosis so lots of back pain) Again, the bathtub was a gift, and it was a cheaper one. I wouldn’t spend a lot on one if you do buy one.
Bassinet- For me, I loved this. It was also a gift and an expensive one too! It rocked and had a little nightlight on it and soothing water sounds. I used it for 3 months and then he went in his crib.(we are not comfortable co sleeping. My husband sleeps so hard and would NOT wake up if he rolled on the baby, I’m sure. I’m too scared to try. Now that our son is 15 months, he sleeps with us sometimes and is big enough to fuss when he gets bumped and what not)
So I guess these are few things that I had that I thought very useful. I guess, I could definitely go without some of these things if I had to. Oh yeah and the walker saved my life, lol! I know some people think they aren’t safe, but by 7 months my son only wanted to be in the walker. He walked at 9 1/2 months. I would have gotten nothing done if it weren’t for that walker. Again, it was a gift. )
Unfortunately, my son would not breastfeed for numerous reasons I won’t get into here. I tried for 3 months and he just wouldn’t do it. Next baby I will see a lactation consultant to make sure my chances are the highest to breastfeed.