I don't know about what kind of armor this is as I am new to this whole thing too, but I recommend not buying anything ebay unless it is from someone that you know from this website.
The reason I say this is that armor is already fitted for someone else, you don't know how big they are (or small they are) and they could have trimmed it to much to ever fit you right without some heavy modifications. For that price you could get a brand new kit that can be fitted for YOU.
Just my 2 cents, take it how you will...