I was also in the same situation as you are now. I also checked what Amazon and others are offering. It doesn't work for me because figuring out what my expenses will be is really messy, impossible to predict at my current development state. Right now I'm using Gamedonia, a cloud service for game development. I contacted them via email and they granted me access to their beta matchmaking based on an ELO system. It was easy to integrate it in my game. Their pricing is independent from API requests and other variables. It's free to use during development, so it fits perfectly my current needs.