即売レジ - 同人誌・フリマの会計 is a productivity app by DDWorks.info with 50,000+ downloads (about 98K estimated). +407 installs in the last 7 days. Install growth, rank history, SDKs and ad networks.
From the store listing: “Accounting support usable for sales events, flea markets, stalls, food stands, live event merchandise sales, and food trucks.”