If you wanted a double buggy to fit a 6 month old and a very heavy toddler, and it was only being used for holidays (so will be battered on luggage carousels) and shoving in the boot of the car would you:
a. Buy the cheapest one in Argos for £80
b. Buy a Maclaren off eBay for about the same price
I'm tempted to just buy from Argos, but the last cheap pushchair we bought lasted about 5 minutes... plus I put my back out every time I push DS in it.
Have never bought a pushchair second hand before though.