The site Etherscan allows you retrieve information on accounts and transactions. There is an interface to the Reposten testnet as well. While doing some work on a project I was monitoring the page to view an account balance and ended up creating a script to do the monitoring programmatically.
The repo listed at the bottom of the page contains the python script which simply parses the page and returns the balance.
The main routine after figuring out which chain the user wants to look at and which account is the get_balance routine. It parses the page and finds the balance in the first table's first row, second cell.
def get_balance(url):
html = requests.get(url, headers={'User-agent': 'Mozilla/5.0'}).text
soup = BeautifulSoup(html, "html.parser")
table = soup.find("table", {"class" : "table"})
value = table.findAll('td')[1].text.split(' ')[0].strip()
return value