Varadero by Bus: From Havana, It will take about 2 hour and a half by bus and costs approximately $10USD/CUC.
Make sure to book your bus ticket at least a day in advance, the buses are frequently sell out a day in advance. You can book your tickets online here, but prices were cheaper at the bus stations.
If you take a taxi from Havana, it will take about 1 hour and half and costs approximately $200USD/CUC. To check more information, click here.
Renting a car is another option. Booking a car rental in Cuba is not easy, make sure to book car several weeks, if not months in advance online.