Cheapest priced copy (Lorwyn): $0.49 at Card Kingdom, near mint, their price list as of .
Twinning Glass 
Artifact · Rare · Lorwyn · #264
{1}, {T}: You may cast a spell from your hand without paying its mana cost if it has the same name as a spell that was cast this turn.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $0.49 to $2.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Lorwyn | 264 | Rare | $0.49 | $2.99 |
3 rulings from Wizards of the Coast
- 1 October 2007It doesn't matter who cast the first spell.
- 1 October 2007You can't pay any alternative costs (such as those from evoke or morph) when casting the card. On the other hand, if the card has additional costs (such as those from kicker or buyback), you may pay those.
- 1 October 2007Activating Twinning Glass's ability allows you to cast a single card from your hand as it resolves. It doesn't create a continuous effect, and it doesn't let you cast multiple cards for free.