Dear Luis,
The idea is good. However, the services on Cash and Insurance will be covered but what about "welfare/charity based" services?
I was searching for some already developed Tryton modules and I found following two:
trytond_product_price_list
tryton_sale_price_list
Using these two modules, multiple price lists can be created and while creating "Sale" a price list can be attached. That works fine and it automatically picks the price from the selected price list. But, I don't see the "Price List" input control in "Health Services"! It would be really nice if we can integrate the "Price List" module with "Health Services".
Further more, I would also request to put some option to attach price lists at patient level.