Mareep is card #14 of 17 in POP Series 7 (2008), a Common illustrated by Atsuko Nishida. At about $7.77 it is the #10 most valuable card in the set. In a POP Series 7 booster it turns up about once every 2 packs. It is one of 28 Mareep cards printed so far.
2000Neo Genesis
2003Aquapolis
2006Dragon Frontiers
2008POP Series 7
2009Platinum
2011Call of Legends
2018Lost Thunder
2021Chilling Reign















See the full POP Series 7 card list
An ungraded Mareep from POP Series 7 sells for about $7.77. A PSA 10 is worth more, roughly $62.16 by our estimate, and a PSA 9 around $21.76.
It is a Common, and it shows up about once every 2 POP Series 7 packs.
Atsuko Nishida drew the art for this card.