Cheapest priced copy (Fourth Edition): $0.35 at Card Kingdom, near mint, their price list as of .
Nafs Asp 
Creature — Snake · 1/1 · Common · Fourth Edition · #264
Whenever this creature deals damage to a player, that player loses 1 life at the beginning of their next draw step unless they pay {1} before that draw step.
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern
6 printings · $0.35 to $2.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Fourth Edition Foreign Black Border | 264 | Common | — | — |
| Fourth Edition | 264 | Common | $0.35 | — |
| Arabian Nights | 52 | Common | $2.49 | — |
| Arabian Nights | 52† | Common | — | — |
| Renaissance | 151 | Common | — | — |
| Rinascimento | 132 | Common | — | — |
4 rulings from Wizards of the Coast
- 4 October 2004If it damages a player twice, they get to pay or take damage twice during their next draw step.
- 4 October 2004The ability does not cause itself to trigger again. It cause loss of life, and not damage.
- 4 October 2004If its damage gets redirected to its controller, it will still trigger the ability.
- 4 October 2004The player can pay the {1} mana at any time after damage is done before the draw step of that player’s turn. People commonly pay during upkeep.