Cheapest priced copy (Guilds of Ravnica): $1.49 at Card Kingdom, near mint, their price list as of .
Risk Factor 
Instant · Rare · Guilds of Ravnica · #113
Target opponent may have Risk Factor deal 4 damage to them. If that player doesn't, you draw three cards.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
3 printings · $1.49 to $2.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Guilds of Ravnica | 113 | Rare | $1.49 | $2.49 |
| Guilds of Ravnica Promos | 113p | Rare | $1.49Out of stock | $2.49 |
| Guilds of Ravnica Promos | 113s | Rare | — | $1.99Out of stock |
5 rulings from Wizards of the Coast
- 5 October 2018If an effect allows you to pay an alternative cost rather than a spell's mana cost, you may pay that alternative cost when you jump-start a spell. You'll still discard a card as an additional cost to cast it.
- 5 October 2018You must still follow any timing restrictions and permissions when casting a spell with jump-start, including those based on the card's type. For instance, you can cast a sorcery using jump-start only when you could normally cast a sorcery.
- 5 October 2018A spell cast using jump-start will always be exiled afterward, whether it resolves, it's countered, or it leaves the stack in some other way.
- 5 October 2018If the target player is an illegal target by the time Risk Factor tries to resolve, the spell doesn't resolve. You don't draw three cards.
- 5 October 2018If a card with jump-start is put into your graveyard during your turn, you'll be able to cast it right away if it's legal to do so, before an opponent can take any actions.