Cheapest priced copy (Commander 2019): $0.49 at Card Kingdom, near mint, their price list as of .
Commander's Insignia 
Enchantment · Rare · Starter Commander Decks · #13
Creatures you control get +1/+1 for each time you've cast your commander from the command zone this game.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
3 printings · $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2019 | 2 | Rare | $0.49 | — |
| Starter Commander Decks | 13 | Rare | $0.49 | — |
| Tarkir: Dragonstorm Commander | 111 | Rare | $0.49 | — |
2 rulings from Wizards of the Coast
- 23 August 2019Certain cards in other sets with the partner keyword may allow you to have more than one commander. If you do, Commander’s Insignia counts the total number of times you’ve cast each of your commanders.
- 23 August 2019Commander’s Insignia counts each time you’ve cast your commander, even the times it was countered or when your commander spell is still on the stack.