Signed Instax-Style Cheki Circulating Online
Authentic Mion Sonoda autographed cheki (Instax/Polaroid-style photos) appear on platforms like eBay as one-of-one hand-signed collector items—sale prices often around US $60–90 USD

Common Production & Distribution Modes
Cheki were frequently issued at fandom “gacha” events, limited shows, or DVD bundles—as random draw perks or bonuses—not mass-produced merchandise

Typical Market Value in Japan
On Japanese auctions like Yahoo! Auctions, signed Mion cheki often sell for approx.US $60–75, non-signed for $40