Are the followings considered a form of money
prepaid (debit) cards
gift cards (both bank-issued such as American Express gift cards, and store-issued such as Walmart gift cards) ?
Are their balances considered demand deposits, and therefore in M1?
Taking gift cards for example. They seem a form of money, but not exactly. Bank-issued gift cards are more likely to be a form of money than store-issued ones.
They can be used to buy products.
But gift cards are usually not allowed to resell, but I don't understand why they are resold on ebay and many websites if reselling them is illegal.
Cashing the balance of new or used gift cards are usually difficult. Cashing bank-issued gift cards seem more difficult than store-issued ones.
bank-issued gift cards are usually sold above their face values, while store-issued ones are usually not.
bank-issued gift cards can be used to purchase anywhere the bank is accepted (e.g. Amex), while store-issued gift cards can be only in specific stores.