Cheapest priced copy (Magic 2014): $0.35 at Card Kingdom, near mint, their price list as of .
Staff of the Sun Magus 
Artifact · Uncommon · Magic 2015 · #235
Whenever you cast a white spell or a Plains you control enters, you gain 1 life.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.35 to $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Magic 2014 | 222 | Uncommon | $0.35 | $0.49 |
| Magic 2015 | 235 | Uncommon | $0.35 | $0.99 |
3 rulings from Wizards of the Coast
- 18 July 2014If you cast a copy of a card that’s a certain color, the appropriate Staff’s ability will trigger. However, if you copy a spell on the stack without casting that copy, it will not.
- 18 July 2014Most nonbasic lands don’t have basic land types, even if they produce colored mana. For example, Caves of Koilos is neither a Plains nor a Swamp. Having one enter the battlefield under your control won’t cause Staff of the Sun Magus’s ability to trigger.
- 18 July 2014Each of these artifacts cares about any land with the appropriate basic land type. For example, Staff of the Sun Magus’s ability triggers when any land with the subtype Plains enters the battlefield under your control, not just lands named Plains.