How can I improve it? (Beginner food script)

var drink;
var food;
var drinkCost=0; // In Dollars
var foodCost=0; // In Dollars
var foodList=['pizza' , 'burger']; //2 types of food what our kitchen have
var drinkList=['cola' , 'water']; //2 type of drink that our kitchen have
var answer=false;
var foodPriceList=[10,5];
var drinkPriceList=[3,2];

function finalPrice(){
  var final=drinkCost + foodCost;
  return final;
}

//Start with the message
var msg=alert('Welcome to our kitchen! Today we got: ' + foodList[0] + ' which cost ' + foodPriceList[0] + ' $ ');
msg+=alert('And also we got ' + foodList[1] + ' which cost ' + foodPriceList[1] + ' $ ');

//Script (Loop with do-while)
do{

  //Food Section -> Asking which food + how many would it cost
  var food=prompt('Please type your food that would like to order');

  //Add value to Cost
    if (food.toLowerCase()===foodList[0]){
      foodCost+=foodPriceList[0];
    }else if(food.toLowerCase()===foodList[1]){
      foodCost+=foodPriceList[1];
  }

  //What if user didn't typed anything?
    if (food.toLowerCase()===''){
      alert("It seems that you typed something wrong. Please try again!");
      answer=false;
      break;
    }

  //Check the food if it is available
    if (food.toLowerCase()===foodList[0]){
      answer=true;
      alert('You have added ' + food + ' to your chart. That would you cost: ' +foodCost + ' $');
    }else if (food.toLowerCase()===foodList[1]){
      answer=true;
      alert('You have added ' + food + ' to your chart. That would you cost: ' +foodCost + ' $');
    }else if (food.toLowerCase()!==foodList[0]){
      answer=false;
      alert("We don't have that food on our chart. Please select something else");
    }else if (food.toLowerCase()!==foodList[1]){
      answer=false;
      alert("We don't have that food on our chart. Please select something else");
    }


//Drink Section -> Ask for which drink, tells the price, and check if the answers are correct!
var drink=prompt('Please type your drink that you would like to order');

//Add value to cost!
if (drink.toLowerCase()===drinkList[0]){
  drinkCost+=drinkPriceList[0];
}else if(drink.toLowerCase()===drinkList[1]){
  drinkCost+=drinkPriceList[1];
}

//What the user didn't typed anything?
if (drink.toLowerCase()===''){
  alert("It seems that you typed something wrong. Please try again!");
  answer=false;
  break;
}

//Check the drink if it is available

if (drink.toLowerCase()===drinkList[0]){
  answer=true;
  alert('You have added ' + drink + ' to your chart. That would you cost: ' +drinkCost + ' $');
}else if (drink.toLowerCase()===drinkList[1]){
  answer=true;
  alert('You have added ' + drink + ' to your chart. That would you cost: ' +drinkCost + ' $');
//If is not on the list
}else if (drink.toLowerCase()!==drinkList[0]){
  answer=false;
  alert("We don't have that drink on our list. Please select something else");
}else if (drink.toLowerCase()!==drinkList[1]){
  answer=false;
  alert("We don't have that drink on our list. Please select something else");
}


}while(!answer)
  answer=true;
  document.write('You have ordered ' + food + ' and ' + drink  + '.' + ' That would cost ' + finalPrice() + ' $');

console.log('The script is done!');