01:20 $> python3.4 finance.py 
Pair       Trade      Ask      Bid
-------  -------  -------  -------
RUB/EUR  87.1671  91.3397  82.9951
RUB/USD  69.6735  73.004   66.343
RUB/UAH   4.4032   4.6283   4.1795

from decimal import Decimal

import requests
from tabulate import tabulate


def yahoo_finance_query(**params):
    ''' Return the text of the request to the Yahoo finance API
        
        s - ids of entities we wnant to receive. Every stock, index or currency has their own ID.
            If you want to get values of more than one ID, separate them with "," 
        f - properties we ant to get. See
            https://code.google.com/p/yahoo-finance-managed/wiki/enumQuoteProperty
    '''
    return requests.get('http://download.finance.yahoo.com/d/quotes.csv', params=params).text

def get_exchange_rate(fixed_currency, variable_currency):
    ''' Return tuple of last trade, ask and bid prices for given currencies '''
    r = yahoo_finance_query(s=variable_currency + fixed_currency + '=X', f='l1a0b0')
    return tuple(map(Decimal, r.split(',')))

print(tabulate(
        (
            ('RUB/' + currency, ) + get_exchange_rate('RUB', currency)
            for currency in ('EUR', 'USD', 'UAH')
        ),
        headers = ('Pair', 'Trade', 'Ask', 'Bid')
))