diff --git a/coinbase/CoinbaseRPC.py b/coinbase/CoinbaseRPC.py
index 42b13d8..98a48fe 100644
--- a/coinbase/CoinbaseRPC.py
+++ b/coinbase/CoinbaseRPC.py
@@ -15,6 +15,8 @@
 import time
 import urllib.parse
 
+from datetime import datetime, timedelta
+
 # ----- Public Classes --------------------------------------------------------
 
 class CoinbaseRPC(object):
@@ -26,16 +28,20 @@ class CoinbaseRPC(object):
 
     def __init__(self, authentication, nonce=None):
         self.__authentication = authentication
-        self.__nonce = None
+        self.__nonce = nonce
 
 
     def request(self, method, url, params=None):
-        url = self.COINBASE_API + url
+        now = datetime.now()
+        expire = now + timedelta(minutes=15)
+        expire_int = int(expire.timestamp())
+
+        url = self.COINBASE_API + url + "?expire=" + str(expire_int)
 
         method = method.lower()
         if method == 'get' or method == 'delete':
             if params is not None:
-                url += '?' + urllib.parse.urlencode(params)
+                url += '&' + urllib.parse.urlencode(params)
         else:
             params = json.dumps(params)
 
@@ -51,7 +57,9 @@ def request(self, method, url, params=None):
         elif isinstance(self.__authentication, CoinbaseAPIKeyAuthentication):
             if self.__nonce is None:
                 self.__nonce = int(time.time() * 1e6)
-            message = str(self.__nonce) + url
+            else:
+                self.__nonce += 1
+            message = url
 
             if method == 'post' or method == 'put':
                 if params is not None:
@@ -66,7 +74,7 @@ def request(self, method, url, params=None):
 
             headers['ACCESS_KEY'] = auth['api_key']
             headers['ACCESS_SIGNATURE'] = signature
-            headers['ACCESS_NONCE'] = self.__nonce
+#            headers['ACCESS_NONCE'] = self.__nonce
             headers['Accept'] = 'application/json'
         else:
             raise CoinbaseAPIException('Invalid authentication mechanism')
diff --git a/coinbase/__init__.py b/coinbase/__init__.py
index 17f89e9..f912e45 100644
--- a/coinbase/__init__.py
+++ b/coinbase/__init__.py
@@ -66,7 +66,7 @@ def create_button(self, name, price, currency, custom=None, options=None):
             params['custom'] = custom
 
         if options is not None:
-            for key, value in operation.items():
+            for key, value in options.items():
                 params[key] = value
 
         return self.create_button_with_options(params)
@@ -82,7 +82,7 @@ def create_button_with_options(self, options=None):
             'button': response['button'],
             'embed_html': '<div class="coinbase-button" data-code="'
                           + response['button']['code']
-                          + '></div><script src="https://coinbase.com/assets/'
+                          + '"></div><script src="https://coinbase.com/assets/'
                           + 'button.js" type="text/javascript"></script>',
             'success': True
         }