Cheapest priced copy (Shadowmoor): $0.35 at Card Kingdom, near mint, their price list as of .
Hollowsage 
Creature — Merfolk Wizard · 2/2 · Uncommon · Shadowmoor · #69
Whenever this creature becomes untapped, you may have target player discard a card.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $0.35 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Shadowmoor | 69 | Uncommon | $0.35 | $0.79 |
One ruling from Wizards of the Coast
- 1 May 2008If Hollowsage becomes untapped during your untap step, the ability will trigger. However, since no player gets priority during the untap step, it waits to be put on the stack until your upkeep starts. At that time, all your “beginning of upkeep” triggers will also trigger. You can put them and Hollowsage’s trigger on the stack in any order.