https://www.cmegroup.com/markets/interest-rates/us-treasury/30-year-us-treasury-bond.quotes.html. Use the chart link in the table.
I forgot where it was decades back, but taking S&P 500 index then program in prem/discount would give real time ES.
%% Close enough for gov \ i mean private sector work. My favorites are delayed end of day quotes/ or end of month\ really delayed quotes\LOL
Yes it is "free" just like you get free checking if you keep X number of dollars in the account. Have a zero balance at some point, no longer free.