public string Start()
{
_console.Write("Enter Product with Unit Price \n Ex : Product1 UnitPrice \n keep Blank to end");
string[] inputs = _console.ReadTillBreak();
List <Product> products = FetchProducts(inputs);
_console.Write("Enter Rules \n Ex : 3 of A's for 130 OR C & D for 30 \n keep Blank to end");
inputs = _console.ReadTillBreak();
List <IRule> rules = FetchRules(products, inputs);
products = ProductQuantitySet(products);
CalculateProductPrices(products);
ApplyPromotionToProducts(rules);
return(CalculateTotal(products));
}