Cheapest priced copy (Archenemy): $0.35 at Card Kingdom, near mint, their price list as of .
Thunderstaff 
Artifact · Uncommon · Commander 2013 · #267
As long as this artifact is untapped, if a creature would deal combat damage to you, prevent 1 of that damage.
{2}, {T}: Attacking creatures get +1/+0 until end of turn.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
4 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Archenemy | 122 | Uncommon | $0.35 | — |
| Commander 2013 | 267 | Uncommon | $0.35 | — |
| Commander Anthology | 237 | Uncommon | $0.35 | — |
| Darksteel | 153 | Uncommon | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 1 December 2004If Thunderstaff is untapped, it prevents 1 damage from each creature, each time it would deal combat damage to you. So if three creatures with double strike attack you and aren’t blocked, Thunderstaff will prevent a total of 6 damage.