Go to www.boltbus.com.
Click on the "where do you want to go" pull-down menu and select your departing location and arrival location:
New York 33rd and 7th (Service to DC)-By Sbarro's
New York 6th Between Canal & Grand (To DC & Phil.)
Washington, D.C. 11th and G NW
New York 34th and 8th by Tick Tock (Phil. & Bos.)
Philadelphia 30th between Market & Chestnut
Boston South Station -- Gate 21
Next, select a travel date on the pull-down menu. Fare and departing time options will pop up, along with a link to explain payment options.
Pick the one that works best for you and click on "purchase options", unless it says "Walk up Purchase" in which case you must pay as you get on the bus.
Click on Buy Now.
Fill in the following form with credit card information. You will receive an email confirmation which you must print to show the driver when you meet the bus as the location you selected.