The Ho-Oh Legend (111 / 123) card can be found in the Heartgold and Soulsilver set.
Recently sold 8 times and based on those sales is worth around £24.50.
Currently, there are 10 open listings for this card on ebay.
This card sells in the range of £7.59 to £41.41, making it quite volatile.
This Legend card was illustrated by Shinji Higuchi.