Several versions of this coin were issued to commemorate the 50th anniversary of the UK's National Health Service. Most coins are not valuable, but some are.
If you have a 50 pence issued for circulation and it has been circulated, even a little, it is worth 50 pence. But if your coin is special and was issued for collectors only, it can be valuable.
COINS ISSUED FOR CIRCULATION:
worn: face value (50 pence in the UK)
average circulated: face value
well preserved: face value
fully uncirculated: $10 US dollars approximate catalog value
There is a good summary of these spiffy coins over at Chard [PRESS HERE]. CoinQuest thanks Chard for use of their coin photo.
To be valuable, coins issued for collectors must be in their original government packaging.