How much should the Tooth-fairy give these days?

I asked a similar question on FacebookGoogle+, and Twitter earlier this week. Not only that, I asked friends and family to reminisce about their childhood Tooth tales. 

Something so quirky always seems to get a grin and start a tale of times long gone. Most people remember loosing their teeth as a young child, especially receiving that cash reward from the Tooth-fairy. 

The going rate when I was stringing my loose tooth to a door knob was 25p-50p. Now days it seems £20 is not uncommon for a nocturnal visit from the Fairy. However; the over all average is between £2-£5. That is a 700%-1000% increase. No matter the amount I think the Tooth-fairy will always try to leave behind something that will bring about that toothless smile in the morning.