These guys make some pretty good ones. Check em' out if you might like this sort of thing.
I'm not sure, but I think the older ones (at the bottom of the page) up until Choice of Intrigues, are free to play and afterwards you can only do a sort of demo for free and have to pay a couple bucks for the rest. (though they might have changed it since I last played)
I've always looked for games that allow you to immerse yourself into a story/world, so I kinda like these a lot. They're pretty well written and the choices you are given actually make sense and are meaningful.