change checkout button

checkout.tpl

@@ -1638,8 +1638,11 @@
                                 class="margin-bottom btn btn-primary btn-lg disable-on-click spinner-on-click{if $captcha}{$captcha->getButtonClass($captchaForm)}{/if}"
                                 {if $cartitems==0}disabled="disabled"{/if}
                                 >
-                    {if $inExpressCheckout}{$LANG.confirmAndPay}{else}{$LANG.completeorder}{/if}
-                    &nbsp;<i class="fas fa-arrow-circle-right"></i>
+                                {if $rawtotal==0}Kostenlos bestellen
+                                {else}
+                                    {if $inExpressCheckout}{$LANG.confirmAndPay}{else}{$LANG.completeorder}{/if}
+                                {/if}
+                            &nbsp;<i class="fas fa-arrow-circle-right"></i>
                 </button>
             </div>
         </form>