Cheapest priced copy (Modern Horizons 3 Commander): $0.99 at Card Kingdom, near mint, their price list as of .
Angel of Invention 
Creature — Angel · 2/1 · Mythic · Kaladesh · #4
Flying, vigilance, lifelink
Fabricate 2 (When this creature enters, put two +1/+1 counters on it or create two 1/1 colorless Servo artifact creature tokens.)
Other creatures you control get +1/+1.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $0.99 to $11.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Kaladesh | 4 | Mythic | $1.29 | $3.99 |
| Modern Horizons 3 Commander | 166 | Mythic | $0.99 | $2.49 |
| Kaladesh Promos | 4s | Mythic | — | $11.99 |
| Tarkir: Dragonstorm Commander | 109 | Mythic | $0.99 | — |
3 rulings from Wizards of the Coast
- 20 September 2016If you can't put +1/+1 counters on the creature for any reason as fabricate resolves (for instance, if it's no longer on the battlefield), you just create Servo tokens.
- 20 September 2016Fabricate doesn't cause the creature with the ability to enter the battlefield with +1/+1 counters already on it. For example, Weaponcraft Enthusiast will enter the battlefield as a 0/1 creature, then its fabricate ability goes on the stack. Players may take actions (such as casting instants) while the ability is waiting to resolve.
- 20 September 2016You choose whether to put +1/+1 counters on the creature or create Servo tokens as the fabricate ability is resolving. No player may take actions between the time you choose and the time that counters are added or tokens are created.