Examples of recently experienced great value...

http://www.chilternrailways.co.uk/content/£1-offer-booking

I've just booked a train from Birmingham to London on Thursday morning, right in the heart of the peak time (leaving at 7 arriving at 8.30) for just a pound.
Coming back at 10pm is also setting me back just a pound.

Allows me to get to Cromer (and back) to try and get my fieldwork done (again) for just £15...