6 printings of Mountain Valley
They range from $0.21 to $1.26 — a 6× difference for a card with the same name. The set code and collector number printed along the bottom edge are what tell them apart.
| Mirage | MIR 328 | $1.26 |
| Dominaria United Commander | DMC 219 | $0.38 |
| Commander Masters | CMM 1012 | $0.38 |
| Edge of Eternities Commander | EOC 61 | $0.27 |
| The List | PLST MIR-328 | $0.21 |
Not sure which one you are holding? OtterDex reads the set code and collector number off the card and tells you.