Its more if you do it by yourself

So I was in this back ally near the river in Cambridge.

'How much?' I asked this young lady looking for business. 'I only want to know the price.'

She thought - 'For you it will be £10 - unless you want to do it by yourself - in which case it will be £12'

I thought.

'And it will cost £10 each for all the others involved.'

'Erm'

'OK - I'll give you a special deal £2 off each charge.'

'That's good.' I said. 'But...'

'Oh go on.' She said with a smile.

'No - its a bit too windy for a trip on a punt today - maybe tomorrow.'