Organic prosciutto can be quite pricey. Tip: buy best quality meat when possible, and compensate for the price by eating less meat in general (which will also be good for your health).
Where to buy ingredients?
Organic prosciutto: better supermarkets or delis, at Ekoplaza or other organic stores, or at an organic butcher.
Organic cheese: better supermarkets or delis, at Ekoplaza or other organic stores, straight from the farmers.
Wholegrain tortillas: most supermarkets (I buy mine at Hoogvliet), or make your own.