Cheapest priced copy (Urza's Saga): $0.59 at Card Kingdom, near mint, their price list as of .
Stern Proctor 
Creature — Human Wizard · 1/2 · Uncommon · Urza's Saga · #99
When this creature enters, return target artifact or enchantment to its owner's hand.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $0.59 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Urza's Saga | 99 | Uncommon | $0.59 | — |
2 rulings from Wizards of the Coast
- 4 October 2004You can cast this card if there are no artifacts or enchantments on the battlefield.
- 4 October 2004If there is an artifact or enchantment on the battlefield (even your own) when this card enters, you must return one to owner's hand. If not, then simply ignore the "enters" ability.