Here's a cheap way to make your cupcakes look professional...use a bag!
Of course you could go to a craft store and buy some, but you probably already have some in your pantry. FREEZER BAGS!
Freezer bags are stronger than regular ziploc bags. Put your icing in the bag and squeeze it down into a corner.
Snip off the corner.
Starting on the outside edge, squeeze the bag and work your way around the cupcake until you come to the middle.
You could add sprinkles or any other embellishment and people will think you bought them at the local bakery!