Exactly what Ruth said.
I have 2 different experiences. With DD we had terrible feeding issues and I didn't have one. DH had to rush out and get one one Saturday afternoon just so we could feed the poor creature. I used it for a while then put it away. I then went back to work and it became invaulable. I have definitely had my money's worth.
With DS I have retireved it out of storage once, but I have never left him for more than an hour so have to say could really have done without it for him.
So short answer is no, I wouldn't get one before bub and just know where you can get one if you need it.