Cheapest priced copy (Throne of Eldraine): $0.99 at Card Kingdom, near mint, their price list as of .
The Royal Scions 
Legendary Planeswalker — Will Rowan · Mythic · Throne of Eldraine · #199
+1: Draw a card, then discard a card.
+1: Target creature gets +2/+0 and gains first strike and trample until end of turn.
−8: Draw four cards. When you do, The Royal Scions deals damage to any target equal to the number of cards in your hand.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
6 printings · $0.99 to $2.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Throne of Eldraine | 199 | Mythic | $0.99 | $1.99 |
| Throne of Eldraine | 272 | Mythic | $1.99 | $1.99 |
| Throne of Eldraine Promos | 199p | Mythic | $0.99 | $1.49 |
| Throne of Eldraine Promos | 199s | Mythic | — | $2.79 |
| The List | ELD-199 | Mythic | $0.99 | — |
| Secret Lair Drop (Len and Rin, Harmony Incarnate) | 1600 | Mythic | $2.99Out of stock | $2.29 |
4 rulings from Wizards of the Coast
- 4 October 2019If replacement effects cause you to draw five or more cards while resolving the last ability of The Royal Scions, its reflexive triggered ability still triggers only once, even if you draw eight cards.
- 4 October 2019The Royal Scions's last ability goes on the stack without a target. While that ability is resolving, you draw four cards. When you do, the reflexive triggered ability triggers and you pick a target to be dealt damage. This is different from effects that say “If you do . . .” in that you choose a target after looking at the cards you draw.
- 4 October 2019You draw a card and discard a card all while The Royal Scions's first ability is resolving. Nothing can happen between the two, and no player may choose to take actions.
- 4 October 2019If you draw fewer than four cards while resolving the last ability of The Royal Scions, its reflexive triggered ability doesn't trigger.