You can make regular or sugar free, depending on the syrup that you use.
The best ones are the fruity flavors: strawberry, raspberry, mango, etc.
You can buy a big bottle of syrup and Smart & Final for about $5.
Fill a glass about halfway with ice.
Pour about 2 shots (or to taste) of the flavored syrup of your choice.
Fill the rest of the glass with club soda, and stir.
It's ready to drink!