Programs for modding please?

First off, what programs do you use to make custom units? As in take parts from other units and implement them on the said unit you want to customize?
Second, what program(s) do you use to re-colour or re-make the UV map for models? Because I'm making custom outfits for my PDF/PDF2nd/PDX models and I need to know how to make UV maps from scratch.
Replies
Ok, Photoshop it is. But how do I crack it to get it free? Because I'm not paying $70 a month to use it. I'm on Windows 10 and a dell Gaming Desktop.