Explanation
Opportunity cost: It refers to the potential benefit an individual or entity gives up when choosing one option over another. In simpler terms, it's what you miss out on by making a specific choice.
Free commodity by the government: When the government provides a good or service for free, it doesn't eliminate the opportunity cost. The resources used to provide that free good could have been used for something else.
Taxpayers bear the burden: The resources for "free" public goods come from somewhere, usually taxpayer money. So, the opportunity cost isn't eliminated, it's simply shifted. Taxpayers give up the potential use of those resources in exchange for a free good or service.
In essence, while the individual consumer might not directly pay for the good, the cost is still there and borne by the tax-paying public.