Users interact with dapps without tokens
The common model for users to interact with a blockchain is by buying/owning tokens, holding them in a wallet, and signing transactions from that wallet. This can be quite costly, especially with more popular blockchains as their token price is generally high. Once the user acquires tokens, they are often used to pay transaction (or gas) fees to simply use the network. Although this model is nice in theory, it is not practical as very little computation is performed in each transaction which can have a rather large transaction fee. In addition to this, many blockchains run their user interface using cloud service providers. This heightens the cost inefficiency as both the developer and the user pays - the developer for the cloud services, and the user for the blockchain interactions.
Reverse Gas Model (AKA "canister pays")
Internet Computer dapps adopt a "Reverse Gas model" where developers load canisters with computation cycles in advance which in turn allows users to interact with a dapp without having to pay in tokens.
As an example, the Motoko Playground dapp is hosted and executed entirely on-chain and it does not require visitors to pay for the computation: https://m7sm4-2iaaa-aaaab-qabra-cai.raw.ic0.app/. The Internet Identity app is also a free to use application running on the IC.