There is no reason why you can't make a whole pig into sausage and burgers. Yes, there will be a cost to making them roughly a £1 per lb but best check with your butcher. You could make different varieties. Yes, packaging and labelling will need to be paid for but all necessary if you intend to sell on to the public. I would always try the sausage before you have it made. Some butchers double mince and I find that too pasty. Some sausage is too spicy etc. Some people like thin, some thick.
A general cut up would be
shoulders sausage or boned and rolled, minced or diced
loin boned and rolled or chops
legs roasting joints
belly pork strips or roasting joints
Then there's other variations.