Like most Pokmon cards, the value of Chansey depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Mysterious Treasures)
The thing is, it has far worse specific card quality than the black Tutors, most of the time in cube you just want general card quality, the need for finding specific things is dwindling
Tomorrow's Pokemon Card: So thanks for reading today's Pokemon card review of Trevenant from the X and Y set, stay tuned for tomorrow's card review of Pumpkaboo, which is from this same set
These Cards Are Worth How Much
Endless adventure awaits
Given Lost Thunder's age at this point and the rarity of promos, it's not surprising this card is almost extinct on the market