Everybody will be charging at home/work. Other places you'll likely charge are conveniently located places between long distance destinations. Rest areas for example.

Costco might implement chargers at parking spaces as a convenience thing, but if they do it for free they'd have to do it for all parking spaces to prevent people fighting over spaces. I have no idea how such a large-scale charging system could be retrofitted into an existing car park. Seems more likely that if supermarkets etc did want to implement charging in their carparks, they'd install a few and charge a nominal amount.