Fret not, you do not need bags of different sugars. All you need is unbleached granulated sugar and the following tips:
1. Caster sugar: Bung granulated sugar in a blender and blitz.
2. Icing sugar: As above but blitz for longer then sieve.
3. Brown sugar: Add some gravy browning.
4. Sugar cubes: Cowboy up cupcake and get over it.