Flash guns for Location work

I'm looking into getting a flash gun to do more location work with models. I was looking at a sigma just purely because of the price but I'm not sure which model I'd need.
All I know is it's for location work and I'd like it off camera. Preferably cable free but I just don't know how that works.

Perhaps do this. Post a pic of an example lighting you would like to mimic in a location you see yourself shooting at, then someone on this forum who has done it likely will provide some insight as to how you can replicate the effect. That is really what you are after. Then you can experiment from there as you learn how to mimic the effect.

There are just so many questions before we can make a good recommendation and center mainly on the look you are after.

There isn't a photo that I've actually seen that I want to mimic. At the moment I can't afford hunderds upon hundreds to get 2-3 flash guns which I know would be the best option.
I just want a light I can control better than the sun.

Get the Vivitar if you don't have the flash mounted on your camera - this is the best way to do it anyways.