Ubidots offer a free service for up to 5 measurement values.

My setup is Nexa temperatur and humidity sensors that report to a Tellstick connected to Raspberry. Here is the setup:

sudo apt-get install python-setuptools
$ sudo easy_install pip
$ sudo pip install ubidots

Using the api to post data in is only a few lines:

from ubidots import ApiClient
import random

#Create an "API" object

api = ApiClient("4785d3be6f45a6102xxxxxx75efb16a6f9b9c")

#Create a "Variable" object

test_variable = api.get_variable("56294a1xxxxxxx27c3c69d")

test_value = random.randint(1,100)

test_variable.save_value({'value':test_value})

Here is my outside temperatur chart based on a logging once per hour: