These budgets are all relative - some people can manage on 1€ per km on the
Camino Frances and others on .50c per km.
http://caminodesantiago.consumer.es/calculadora/ has this breakdown from Roncesvalles to Santiago:
Making an average of prices for accommodation in a bunk in pilgrim shelters - both private, public and parochial - we have established an average price of 7 euros per night . We contemplate a duty that the pilgrim always leave a donation in the shelters and will ask to find the mean we have considered an extra 5 euros in all these accommodations.
We must also take into account the costs of maintenance (we considered that not every day you eat a couple of times a restaurant), incidental expenses incurred by the use of the washer and dryer, extra costs may be incurred for the purchase of medicines or a visit to some monuments, etc. Generate an average payout of 23 euros per day .
In total, the estimate to be made ​​a pilgrimage to Santiago is 30 euros per day including lodging and meals.
The VF is even harder to estimate. Will you sleep in hotels? Will you camp? Eat in restaurants every day or find places with self catering? Will you be walking in France, Switzerland, Italy - or all of the above? France is quite costly, Switzerland more so, Italy a little cheaper.
Maybe the Pilgrimstorome.org.uk has an estimate?