Even if you’ve done you’re a brilliant job… and picked the perfect high-demand/low-competition product to sell on Amazon, you still have to let the world know about it. And this means advertising…,. and advertising costs money… and therefore will impact your profit margin. So… why advertise? The reality is that… even with good products and reviews… a lot of your business success will come down to the velocity of your sales. So.. you can save by not advertising… but you will likely sell less items per month… or you can spend money on advertising and significantly boost your sales rate.