The M Aggron EX (154 / 160) card can be found in the Primal Clash set.
Recently sold 7 times and based on those sales is worth around £8.61.
Currently, there are 4 open listings for this card on ebay.
This card sells in the range of £2.24 to £14.98, making it quite stable.
This Rare Ultra card was illustrated by 5ban Graphics.
The fact that it is a EX card makes it one of the more valuable cards.