For most people, a 5-10 gram dose will do just fine. I mean, some people will use more, though that's usually set aside for bigger people. I know a guy who's around 285 and he takes over 20 grams a day, though, I doubt very much that he's utilizing a full 20+ grams.
If you keep the doses low, you won't go through the product as quickly and you'll actually get something out of it, seeing your body will utilize it.