What do? Car seat help!

I got a car seat from a friend, (no accidents & not expired) it came with no newborn insert. I’ve went to Gracos website and tried to order a replacement and they no longer sell them. Idk what to do. I dont want to buy a newborn insert not meant for the seat but I might have to.

I’ve tried looking on Facebook marketplace for the same car seat with the newborn insert but it’s either ones bought after the car seat, they no longer have the insert, or they just ignore me.

Anybody have any ideas?