Cheapest priced copy (Mirrodin Besieged): $1.49 at Card Kingdom, near mint, their price list as of .
Phyresis 
Enchantment — Aura · Common · Mirrodin Besieged · #49
Enchant creature
Enchanted creature has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
2 printings · $1.49 to $16.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Mirrodin Besieged | 49 | Common | $1.49 | $16.99 |
| The List | MBS-49 | Common | $4.49 | — |
One ruling from Wizards of the Coast
- 1 June 2011Multiple instances of infect on the same creature are redundant.