My kids are older now but I agree with the less is more concept. For our first we had so many little sleepers and onesies it was crazy. No way did he he even wear them all once.
I would say
-buy a good new infant carseat. It really is easier and you need one you can trust. You can use it for your 2nd if it is not too old.
-I would be okay with a used bed if I knew it had not been recalled and especially if it was a friend. I would buy a new mattress though, they are not expensive in the realm of stuff.
-wait til after your shower to get clothes and blankets, then buy only what you need (like a weeks worth per size) If you do not have a washer buy more, if you do you can buy a little less. For sure wait til later in your pregnancy and see if your dr estimates the baby's size. Our 2nd weighed 10lbs (and the dr told me he would be close to that) I think he never wore newborn clothes and only wore the tinest diapers for about a week. We did buy one special outfit for each child and I kept those, just like my mom kept ours.
-For blankets you need a couple larger ones (for covering carseat and floor play) and several swaddling, cotton ones. But you will probably get both of those at a shower easily, probably more than you can ever use

I had like 40 blankets in asst sizes
-get a thermometer, when you need it you need it right then
-breast feed if you can and get a pillow! The pillow is so helpful, those babies get heavy after a while, the pillows are so worth it. I would buy new for that too. You want it clean and firm, not mashed down. I used a new one for every child. I would get a new pump, if you can, but I just used a little handheld one since I was home, but if you go back to work a bigger one would be lots better and worth the money
-a play and go/playpen type thing is really good to have too and I would buy new for that because the mesh on the sides and the mats for bottom are hard to make sure they are super clean I think. But you really don't need it right away
Basically if you can wash it in hot water/bleach it you can do used, if it is sturdy and not recalled. SO much of that stuff is hardly used at all. If you have a good friend who will sell you stuff (and you know her house is clean, not just a friend from work who shows up together there, make sure you see the house) then you can get some good deals
It is worth not buying too much stuff to be able to stay home longer

I think. I would start buying some diapers though if you can, they really add up faster than you think, just having some to start always made me feel like at least one thing was 'free'
Have fun getting ready