buying a car seat

I have to agree, it's best to buy from new. Car seats should not be used after five years usage as materials do get worn which you cannot see, plus if it has been in a crash again, the extent of the damage to the seat is unknown.

I appreciate the comments where people say I would rather buy a second hand car seat that did well in safety tests than a cheap Argos one that may not have done so well, but... you have several months when your pregnant to save and look out for deals, and once baby is born you already know they will need a new seat and have time to save/look for offers. I think certain things are completely fine to buy second hand but car seats and mattresses are the two things you should buy new if you can.

I'm an ex-biker & safety Nazi in some circumstances. A very well loved & cared for seat might do for an emergency, but I prefer my own kit, sourced from new.
Just my paranoias. Other mothers have bought & sold second hand and been fine.

If the carseat is in excellent condition, and was a good model when purchased, not more than 5 years ago, I would choose it over the cheapest seat you could buy new. I think Which? magazine did carseat reviews and found many of the cheap ones to perform very poorly. If it is a baby carrier seat that baby will not be in for long then I'd use the one offered, and save the money to put towards a good, bigger carseat later on.