Sell vouchers from the website, paid up front, redeemed by QR at the counter.
Pick an amount, add a message, pay. The recipient gets a voucher with a QR code by email or text. At the counter, staff scan it with a phone, see the balance, enter the amount used — partial redemptions just work. The owner sees what's sold, what's outstanding and what's been redeemed.
Demo tenants are only listed behind the preview gate.