I use to use a Samsung Stratosphere, but due to my sister convincing my dad I didn't need a smart phone I now have a basic phone. I want to unlock my stratosphere so I can use it through Straight talk. So how do I unlock my Stratosphere, for free? & is it possible that once I unlock it I can use it through straight talk, and if not, if I buy a sim card from straight talk and put it in my stratosphere then will it work? Thanks so much for any help!