Cheapest priced copy (Ravnica: Clue Edition): $0.49 at Card Kingdom, near mint, their price list as of .
Lavinia of the Tenth 
Legendary Creature — Human Soldier · 4/4 · Rare · Dragon's Maze · #80
Protection from red
When Lavinia enters, detain each nonland permanent your opponents control with mana value 4 or less. (Until your next turn, those permanents can't attack or block and their activated abilities can't be activated.)
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
3 printings · $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Ravnica: Clue Edition | 199 | Rare | $0.49 | — |
| Dragon's Maze | 80 | Rare | $0.49 | $0.49 |
| RNA Guild Kit | 15 | Rare | $0.49 | — |
8 rulings from Wizards of the Coast
- 15 April 2013If a creature is already attacking or blocking when it's detained, it won't be removed from combat. It will continue to attack or block.
- 15 April 2013When a player leaves a multiplayer game, any continuous effects with durations that last until that player's next turn or until a specific point in that turn will last until that turn would have begun. They neither expire immediately nor last indefinitely.
- 15 April 2013If a noncreature permanent is detained and later turns into a creature, it won't be able to attack or block.
- 15 April 2013Activated abilities include a colon and are written in the form "[cost]: [effect]." No one can activate any activated abilities, including mana abilities, of a detained permanent.
- 15 April 2013The static abilities of a detained permanent still apply. The triggered abilities of a detained permanent can still trigger.
- 15 April 2013The mana value of a creature token is 0 unless that token is a copy of another creature, in which case it copies that creature's mana cost.
- 15 April 2013Lavinia's ability doesn't affect permanents an opponent gains control of after its enters-the-battlefield ability has resolved. Similarly, if you gain control of a detained permanent after that ability resolves, it will continue to be detained until your next turn.
- 15 April 2013If a permanent's activated ability is on the stack when that permanent is detained, the ability will be unaffected.