1
The only way people can help you is if they know your itinerary...That said, probably the regular JR pass to use as you leave Tokyo.
But it depends on your route and timeframe.
You can price individual legs on the Shinkansen on hyperdia.com
Buses are also an option.
2
As Tokyo girl writes, tell us about your itinerary in detail and whether you are looking for the absolutely lowest cost (which usually means highway buses,) or whether you prefer comfort (i.e. trains).
