You can run this bot to Get usd to rub exchange rate.
It will send every 3 hours message with current rate in your chat in telegram.
For Get it uses https://exchangeratesapi.io (Exchange Rates API) - for free 250 requests per month.
You need to make tokens.py with tg_token (telegram token of your bot).
and exch_token (exchangeratesapi.io token).
Or you can add two variable in usd_rub_tg_bot.py with delete import.
Good luck.