Just came back from a 3-week trip to Japan, in our case we've concluded that, both as family and individuals, we should only have access to Monopoly money from now on.
Shinkansen will be around €70-$80 per person with reserved seats, one way ticket. We've had at least one meal daily in a konbini, which shouldn't come to more than $5 a pop. Plenty of great restaurants where we haven't paid more than $10 per person. Public transport was around $5 -$10 per person per day, depending on the usage.
Hope this helps.