FOILCheapest priced copy (Zendikar Rising Commander): $1.49 at Card Kingdom, near mint, their price list as of .
Hour of Revelation 
Sorcery · Rare · Hour of Devastation Promos · #15s
This spell costs {3} less to cast if there are ten or more nonland permanents on the battlefield.
Destroy all nonland permanents.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $1.49 to $29.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Hour of Devastation | 15 | Rare | $1.79 | $4.49 |
| Hour of Devastation Promos | 15p | Rare | $1.99 | $29.99 |
| Hour of Devastation Promos | 15s | Rare | — | $5.49 |
| Zendikar Rising Commander | 17 | Rare | $1.49 | — |
2 rulings from Wizards of the Coast
- 14 July 2017You determine the cost to cast Hour of Revelation before you pay any of that cost. For example, if the only nonland permanents on the battlefield are Tezzeret the Schemer and nine Etherium Cells he’s given you, Hour of Revelation costs {W}{W}{W} to cast. You may sacrifice three Etherium Cells to pay this cost, even though there are no longer ten or more nonland permanents after you produce {W}{W}{W}.
- 19 January 2018There are many important moments in the story, but the most crucial—called “story spotlights”—are shown on cards. These cards have the Planeswalker symbol in their text box; this symbol has no effect on gameplay. You can read more about these events in the official Magic fiction at http://www.mtgstory.com.