I actually bought two batteries. One off of EBay and another from Lazada. I would suggest getting one that has the tools to also help open the case. There is a thread about opening the case and a link to video. It isn't that hard but does require patience.
My battery issue was that when it reached 30% my Tab Pro would just shut off. I would only get 2 hours or so of battery life. I did reseat the battery before I bought a replacement and that helped. I decided to replace it anyway and I am glad I did. I am getting a lot better battery life now.