This is one of my concerns. We have spent years becoming AWS "experts" and while I want to save money, I also feel really comfortable with Amazon and their offers. We don't use a lot of custom solutions from AWS and are not heavily invested in devops peeps, so the dev staff serve both needs.
I can't say our bill from AWS is horrible, but I have challenged our team to reduce costs to try and make our process more cost effective so I can hire 1-2 more people. DO came up as an option. Not that we are spending that much with Amazon alone but that it may be an option to help save some money. To be totally honest, AWS has been so awesome to us it is hard for me to imagine leaving them, but I can't be blind to saving some cash. Thanks for the opinion and option.