Add free mention

Author: mtth

resources/examples/fantasy-premier-league.ipynb

@@ -259,7 +259,7 @@
       "metadata": {},
       "source": [
         "<div class=\"alert alert-block alert-warning\">\n",
-        "    &#9888; You will need an Opvious API access token to run the function above since the data size exceeds the limit for guest solves. Once you've created one <a href=\"https://hub.cloud.opvious.io/authorizations\">here</a>, simply edit the cell above and insert it where indicated.\n",
+        "    &#9888; You will need an Opvious API access token to run the function above since the data size exceeds the limit for guest solves. Once you've created one <a href=\"https://hub.cloud.opvious.io/authorizations\">here</a> (signing up is free), simply edit the cell above and insert it where indicated.\n",
         "</div>\n",
         "\n",
         "Let's see what we get when solving with the default parameters (note the three columns on the right which indicate whether a player is on the starting roster, is captain, and is vice-captain)."

resources/guides/welcome.ipynb

@@ -245,7 +245,7 @@
         "## Next steps\n",
         "\n",
         "+ Browse our other interactive [guides and examples](https://www.opvious.io/notebooks/retro)\n",
-        "+ Create your account via the [Optimization Hub](https://hub.cloud.opvious.io) to solve larger problems\n",
+        "+ Create a (free) account via the [Optimization Hub](https://hub.cloud.opvious.io) to solve larger problems\n",
         "+ Try the platform out locally via the [self-hosted API server](https://hub.docker.com/r/opvious/api-server)"
       ]
     },