You don't need realtime option quotes - until you are ready to make a trade. Yahoo Finance gives you option quotes that are about 20 minutes delayed. You can easily estimate the current value by checking the Yahoo Finance stock quotes and 1-day chart - which are in realtime. When you are ready to trade login to your broker for final quotes.
Some free sources of 10-20 min delayed option prices. https://www.optionseducation.org/toolsoptionquotes/optionsquotes https://optionstrat.com https://www.barchart.com/options