Buying a second hand products can be very tricky, as you can buy a seat wich was in the accident,
Looking into auctions if you are not sure about item, you can ask before bidding if it was involved in any accidents ,but if you are not sure about response( example: no photo, poor quality photo, or seller has a low feedback or no feedback at all, or picture from other auction saying the on sale is identical seat, or picture from a web cite with a new seat but on sale is a used one( you should see what you are buying), -then better go to a different auction
Always ask the seller how old is a seat, as there is a legal requirement that the seat over 10 years could be used by the owner but it could not be sold to others( keep in mind there is safety reasons for it).
When you picking up your seat, ask to have a look at it, you can take briefly cover of the sides and search if any changes in plastic have appeared ( seat may be damaged and not noticed) ,Check before you buy we talk about your childs safety and you paying money for it, the seller of the second hand goods has the same legal rights as the shop. Also second hand Car seat can't be sold as it is( so beware such sellers and you can easily report such listings to ebay to be removed)
CHILD car seat is a safety device to protect your child, if it is not serving to its purpose ( and has faults) then it should not be sold but disposed!
From my own experience I would rather recomend used carseat buy only from friends you know, or from a trusted sellers with good feedback. Sometime you can find a bargain of the brand new car seats on e-bay, make sure they are certified to safety standards( remember - legally there are no such term like factory seconds on a child car seats)
Hope this little tips will help you to make a rights decision and avoid mistakes.
Please, do not forget to vote for this guide, so others can take advantage of this useful info.
Thanks for voting