I collect Hot Wheels and got tired of spreadsheet tabs and apps that make you sign up and pay every month. I built Die Cast Shelf for iPhone and iPad: shelf, wishlist, and trade list. Scan a barcode in the aisle or at home. Free tier is 50 cars with the offline catalog, duplicate checks, and export. Pro is $9.99 once for unlimited cars and Peg Hunt at the store. iCloud sync is optional and uses your Apple ID.