They won't let you out of the hospital to take the baby home unles you have a car seat. I say buy a good quality inexpensive one, it will come in handy for other trips, for instance, you might buy a pram with a car seat that clips on, thats really handy, or if you need to take a taxi another time. I say just bite the bullet and get one, better safe than sorry. I would not get a second hand one, you don't know where it has been and it might not be safe. You can get a Mothercare brand one for £50, money well spent imo.