I personally do not think you have any risk with Amazon. It does not sound like you have a liquidation method for amazon credits other than spending. I do think you should learn how to MS. If you are willing to do this and you have this bank roll, MS will be much, much more profitable. You should still buy Amazon gift cards, better yo get 5x on your real spend, but learn about manufactured spending. 1MM UR points is great to make, even better to use that amount annually.