what's the real cost of the mythical 'free' market?

I'd be the first to admit that, as a general rule of thumb, you can't change human nature.
Example. There's nothing wrong with communism in its purest sense but as applied, historically, it has too often brought out the worst in humanity: criminality, genocide, elitism and privilege, incompetence, lack of accountability, exploitation, suppression and repression.
Substitute communism with Catholicism or Islam (or any cult you like) and you'll observe a similar phenomenon: the finest altruistic principles corrupted by human opportunism and manipulation.
Another time, I'll look at this phenomenon a little more closely.
Suffice it to say, most communist states have broken down because the vision, in practice hasn't matched the theory – thanks to human nature.
Why? Too many of us don't really believe, in our hearts, that we are no better than everyone else.

A global economy underpinned by the 'principles' of Supply and Demand is humanity's panacea.
Damn! I didn't vote for it but I'm really impressed!
As with most noble precepts, capitalism works - on paper …
Production and consumption increasing in harmony, in equilibrium.
Innovation, excellence and hard work rewarded: wealth for all!
Mutual obligation - so no free rides at society's expense.
Productivity and Competition keeping prices down; mediocrity and underperformance penalised.
'Just In Time' management offering efficiency gains to benefit the marketplace.
(insert your favourite cliché here)

How much needs to go wrong before our collectively-thick-as-pigshit human nature perceives that the free market is a complete crock?
Six billion of us live in a closed system which can't sustain anything approaching continual growth.
In fact, if we all stopped breeding tomorrow, our manufactured environmental crisis is still inevitable.

When I was in high school 35 years ago, we learnt that a quarter of the world's population lived in poverty.
Thanks to the market, they still do.

As for aspirationalist 'working families' - a favoured tool of the overpaid and largely underworked notional 'left' here in Australia - this term needs to be replaced with 'WORKING POOR'.
REAL workers are being screwed worse than ever.