$.post({
  url : "price/getprice",
  data : {"options" : chosenOptions},
  success : function(data) {
              $("#price").text(data);
            }
});

http://localhost:42427/Product/Details/%5Bobject%20Object%5D

$.post({
  url : "/price/getprice",
  //     ^-- leading slash
  data : {"options" : chosenOptions},
  success : function(data) {
              $("#price").text(data);
            }
});

<% = ResolveUrl("~/price/getprice") %>

$.post({
  url : "http://mywesbite.com/price/getprice",
  data : {"options" : chosenOptions},
  success : function(data) {
          $("#price").text(data);
        }
});

$.post({
  url : "/price/getprice",
  data : {"options" : chosenOptions},  <<<<< Right here. dang.
  success : function(data) {
          $("#price").text(data);
        }
});

$.post({
  url : "/price/getprice",
  data : { options : chosenOptions},  <<<<< no quotes. arg.
  success : function(data) {
          $("#price").text(data);
        }
});