Remember that referring 3 of your friends, gets your card for free. 25% of those could be free, increasing the acquisition cost. Couple that with the recent $

Remember that referring 3 of your friends, gets your card for free. 25% of those could be free, increasing the acquisition cost. Couple that with the recent $175m investment Amazon made, and yes, it is expensive. Is it a good investment? Bezos makes few mistakes.