Cheapest priced copy (The List): $0.49 at Card Kingdom, near mint, their price list as of .
Swans of Bryn Argoll 
Creature — Bird Spirit · 4/3 · Rare · Shadowmoor · #151
Flying
If a source would deal damage to this creature, prevent that damage. The source's controller draws cards equal to the damage prevented this way.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
3 printings · $0.49 to $11.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Masters 2015 | 199 | Rare | $0.59 | $2.49 |
| The List | MM2-199 | Rare | $0.49 | — |
| Shadowmoor | 151 | Rare | $0.79 | $11.99 |
5 rulings from Wizards of the Coast
- 1 May 2008If a spell is causing damage to be dealt, that spell will always identify the source of the damage. In most cases, the source is the spell itself. For example, Burn Trail says “Burn Trail deals 3 damage to any target.”
- 1 May 2008If the source of the damage is a permanent, Swans of Bryn Argoll checks who that permanent’s controller is at the time that damage is prevented. If the permanent has left the battlefield by then, its last known information is used. If the source of the damage is a spell, its controller is obvious. If the source of the damage is a card from some other zone (such as a cycled Gempalm Incinerator), Swans of Bryn Argoll checks its owner rather than its controller.
- 1 May 2008The source of combat damage is the creature that deals it.
- 1 May 2008If a creature with wither would deal damage to Swans of Bryn Argoll, that damage is treated just like any other damage. It’s prevented, and the creature’s controller draws cards. Swans of Bryn Argoll doesn’t get any -1/-1 counters.
- 1 May 2008If an ability is causing damage to be dealt, that ability will always identify the source of the damage. The ability itself is never the source. However, the source of the ability is often the source of the damage. For example, Knollspine Invocation’s ability says “Knollspine Invocation deals X damage to any target.”