Free charging while superficially great is actually one of the worst ideas, be that as supermarkets, town centres etc. Before you hit "disagree" , and I'm with Jason, it just drives people to use them, not because they need them, but because they can save a few quid, or because the bay is a foot wider or 40 paces closer to the entrance to where they are going.
Ask yourself this simple question, when you NEED to charge, would you prefer to find an available charger that cost as little as a £1 connection fee (which is all they introduced near me) or to see all the chargers occupied by people who don't need to charge but are freeloading? That £1 made the difference at my local railway station between them all being used to hardly any being used. I also used to drive to Manchester and arrive at the car park after 8:30 and all the charging bays were full, it's got to be better to have available ones for those that have travelled for maybe 2 hours to work in Manchester to be able to charge than give free charging to the locals?
Instead of free, I'd want working, a decent rate, and enforced parking rules. Now we can't always find the latter, but while we have the former then the latter will never be affordable.