Cheapest priced copy (World Championship Decks 1998): $0.79 at Card Kingdom, near mint, their price list as of .
Dwarven Thaumaturgist 
Creature — Dwarf Shaman · 1/2 · Rare · Weatherlight · #98
{T}: Switch target creature's power and toughness until end of turn.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $0.79 to $1.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| World Championship Decks 1998 | br98sba | Rare | $0.79 | — |
| Weatherlight | 98 | Rare | $1.79 | — |
4 rulings from Wizards of the Coast
- 1 November 2005Note that the wording "Effects that alter the creature's power alter its toughness instead, and vice versa, this turn" has been removed.
- 19 March 2021Switching a creature's power and toughness twice (or any even number of times) effectively returns the creature to the power and toughness it had before any switches.
- 19 March 2021Effects that switch a creature's power and toughness apply after all other effects, regardless of when those effects began to apply. For instance, if you target a 1/2 creature then give it +2/+0 later in the turn, it's a 2/3 creature, not a 4/1 creature.
- 19 March 2021Because damage remains marked on a creature until the damage is removed as the turn ends, nonlethal damage dealt to a creature may become lethal if you switch its power and toughness during that turn.