Yes I think that was parking cost not bus cost they were talking about (buses can be expensive for short journeys but the cost usually doesn't rise that much for longer ones in my recent experience - I paid £3 for a 40 min journey last week. But bus fares were capped at £2 for ages so I don't have a good feel now for what they cost).

Parking in premium areas can certainly be £5 an hour - but that really will be for premium areas with few spots and high demand, although that's a common situation in historic town centres. I wouldn't be mad enough to try and park in London but I'd expect parking there to be through the roof. The places I usually park for shopping etc (outside London but still SE) are more like £1 an hour in town centres, or free when the car park belongs to a shop or is in a less on-demand area.