EmojiBot solves the issue by doing transactions off the network. This enable users to tip or airdrop as many times as they wish without spending Ethereum.
The EmojiBot is powered by an erc20 token called the emojitoken. There is a gas fee of 0.25 emoji for every transaction. Why have a gas fee? Erc20 tokens retain their value by the amount of utility they have. Most erc20 tokens that are tradable have zero utility either because they are in early development or no utility was given to the token. Emojitoken has multiple use cases. Emojitoken also has a fixed supply. The utility of the token will keep it in high demand and the fixed supply will help it retain value.