From the MSE newsletter:
Oyster Card £5 out of London returns
Online
From 26 June until 25 July Oyster Card and Freedom Pass is offering £5 off-peak returns out of London to several UK destinations when you print a special voucher. Yet anyone can get an Oyster card for £3 (refundable when you hand back the card) to access the deal.
To get the offer, fill in and print out the Days Out Guide voucher & show it to the booking office at your chosen London terminal to get the cheap ticket:
http://www.daysoutguide.co.uk/oyster-voucher
Destinations include Brighton, Liverpool, Southampton, Stratford upon Avon and more, prices range from £5-£20 for either a day or month return. For example:
£5 return: Brighton, Bognor Regis, Eastbourne, Littlehampton or Southend-on-Sea.
£5 return: Arundel, Chichester, Dorking or Windsor.
£10 return: Oxford or Cambridge.
£15 return: Salisbury, Stratford-upon-Avon or Winchester .
£15 return: Birmingham, Liverpool or Southampton.
£20 return: Bournemouth, Bristol, Cardiff or Norwich.
See a full list of destinations included in the offer.
For an example of the savings you can make, an off-peak one month return from London Euston to Liverpool Lime Street would cost c. £65 (depending how far in advance you booked it), but with the Oyster Card special voucher would cost just £15, saving a hefty £50.
Or an off-peak day return to Brighton from London Victoria would normally cost c. £17 (again, depending when you booked it) but would be £5 with the Oyster Card voucher.
If you don't have an Oyster Card, get one at London stations at some shops or order it online from TFL and it'll be posted out first class.You'll have to p*y a £3 deposit for the card and can top it up a minimum of £5.