I make strawberry syrup using the follow ingredientes.   1 pound of strawberrys; half lemon juice; 1 cup of sugar.   How can I make a sugar free (or at least using less sugar) strawberry syrup? 
You can make your strawberry sauce syrup without sugar easily just by replacing the sugar with stevia and then adding it to a proper amount of gelatin water for the proper consistency. It won't be the same for sure but it will be almost sugar free and thicker than water but not have the exact consistency of a syrup. Maybe a little xanthan gum along with the plain gelatin would be a little closer though.  