Make sure there are pics of what they are selling. Ask as many questions as you need to, in order for YOU to feel good about it. Only buy from sellers who have good feedback. Nothing from ebay will have a warranty, so only buy things you know that are quality built in the first place. I've bought all my Alpine decks on ebay and have not had any problems with them. I've also bought some Kicker subs from there. Ebay is a pretty good place to piece out a system on a budget....