You have a good start to something here, but I was a little confused by the mechanics.  There's trading between money and stars, but having one or the other, it wasn't clear what I could do with them (maybe there wasn't anything yet).

The UI for trading also confused me a bit.  It might be clearer with an arrow from one resource to the other so you can tell which you're exchanging for which.

I love the Idea of a Reputation system. With more time you could really make something out of that.