One purchase gets you a total of 10 seeds, which is a good way to start if you're new to gardening or to chile peppers in particular.
One problem with this product is that you need a psychic in order to be able to know what the ghost peppers look like and how big they are, since to you they will be invisible. The ghost peppers will also be difficult to eat because your hands just go through them and you can't grab them.
The worst thing is though that since they are ghosts, they make creepy sounds at night. And whereas for ordinary ghosts, you know that the "unfinished business" they still have to settle before they can move on from this world will be something relatively straightforward (such as saying a final goodbye to a loved one), you really don't know what the frack you're supposed to do with ghost peppers. What is their unfinished business? It's probably some argument with other peppers, or some such crap, and it's very difficult to get involved with that, so be prepared to be haunted by these peppers for a fricking long while.
Even still, for more adventurous growers, I recommend these peppers, but with a caution.