Best way to get started is to take the class offered by the Beekeepers Association of Northern Virginia (
http://www.beekeepersnova.org/ ). The class is $100 and includes membership in BANV, and all the course materials.
The cost of getting up and running will vary depending on how much work you want to do yourself and how many colonies you want to keep. Some people build everything from scratch, including painting, etc. Others buy partially assembeled, painted components, which are more expensive but considerably less work.
This is a good website for buying supplies which will give you an idea of costs:
http://www.brushymountainbeefarm.com/