330ml same price as 500ml, about £1.80 for either size in the supermarkets. large brewery brands do 500ml cans cheaper though, so conclude 330ml is favoured by the craft breweries because the higher margins.
You can’t really compare craft beer to Fosters etc. Macro lagers have lower hop content, made with rice etc. Compare craft with craft and 350 or 500 per ml should be similar