Cheapest priced copy (Future Sight): $0.35 at Card Kingdom, near mint, their price list as of .
Mesmeric Sliver 
Creature — Sliver · 2/2 · Common · Future Sight · #53
All Slivers have "When this permanent enters, you may fateseal 1." (To fateseal 1, its controller looks at the top card of an opponent's library, then they may put that card on the bottom of that library.)
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
2 printings · $0.35 to $3.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Future Sight | 53 | Common | $0.35 | $3.49 |
| Secret Lair Drop | 620 | Rare | — | $0.69 |
3 rulings from Wizards of the Coast
- 1 May 2007This ability triggers when Mesmeric Sliver itself enters.
- 1 July 2013If the creature type of a Sliver changes so it's no longer a Sliver, it will no longer be affected by its own ability. Its ability will continue to affect other Sliver creatures.
- 1 July 2013Abilities that Slivers grant, as well as power/toughness boosts, are cumulative. However, for some abilities, like flying, having more than one instance of the ability doesn't provide any additional benefit.