<form>
                    <select name="event_option" onchange="showPrice(this.value)">
                      <option value=""> Wybierz opcję</option>
                      @foreach ($options as $option)
                      <option value="{{ $option->id }}">{{ $option->name }}</option>
                      @endforeach
                    </select>
                  </form>

                  <script>
                    function showPrice(str) {
                        if (str == "") {
                            document.getElementById("price").innerHTML = "";
                            return;
                        } else {
                            if (window.XMLHttpRequest) {
                                // code for IE7+, Firefox, Chrome, Opera, Safari
                                xmlhttp = new XMLHttpRequest();
                            } else {
                                // code for IE6, IE5
                                xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
                            }
                            xmlhttp.onreadystatechange = function() {
                                if (this.readyState == 4 && this.status == 200) {
                                    document.getElementById("price").innerHTML = this.responseText;
                                }
                            };
                            xmlhttp.open("GET","getprice.php?q="+str,true);
                            xmlhttp.send();
                        }
                      }
                    </script>

                  <p id="price">  </p>