You will need to be a Registered Dietitian.
When I see the word "sugar free", I picture sweet stuff, sugar free granola, sugar free candy bars, or sugar free muffins or whatever you want to call them. I love sweet stuff, so it makes me feel great. I am a little overweight and don't like the feeling of a little sugary food in my mouth. For the record, I am not saying that any of the following are sugar free. They may be high in calories or contain sugar. But that doesn't mean I'm going to eat them all! I'm just saying I don't eat them every day. I don't believe in junk food, but if you want a "sugar free" item, you will be able to buy the sweet stuff that will be low in calories and sugar. The key to this is to choose one that does not contain sugar or any additives.
Most of the sweeteners are not the same in every type of product. So you will need to decide which kind of product to buy based on the item you will be using the product in. The sweetness of the product will also play a factor in whether you use it in place of a sugar substitute or a sugar drink.