Radio question

I have been looking at getting my license for awhile now. I am currently in the public service field ( vol firefighter and LEO) My question is can you use a commercial radio as a ham radio? And can one be used if it is narrow banded? I want a radio that will not break the bank, so I have been looking at Wouxun KG-UV6X, KG-UV3D and Tera TR-590.



Thanks

Radio question