Does anyone know a game that fits this description?

I want a game that takes place in the old west of the United States. I would like it to be an RPG somewhat similar to runescape (as in you can trade with people and get money to buy items). I want to be able to build my own ranch but be able to leave it and explore the world and possibly get small tasks. I also want it to be free and have decent graphics. Any suggestions would be much appreciated. Thank you very much!