Do you want to use this for s3 or dynamo?
If you are looking for storing data, dynamo might be a good option and for images/sounds/textures you could use S3. Although I did not play with it in playmaker, it works just fine. There are a few examples and a demo scene to play with.
Another way is to use RESTful services in Unity, there is a little wrapper that I like
https://github.com/vedi/restifizer-unity3dIt supports pretty much every request you need to handle data:
GET,
POST,
PUT,
PATCH,
DELETE.
Benefit of using Restful and something like Dynamo, is that you can share the same data between different clients of the application/game.
Also parse.com is awesome and has integrations for unity3D.
https://github.com/ParsePlatform/Parse-SDK-dotNETIt shouldn't take much time to write actions for these too. I'm a bit busy at the moment but I wouldn't mind having a go.