The Lightning network is arguably the cheapest form of blockchain payments in existence. Other blockchains do offer fast and cheap transactions, however they often suffer from some form of centralization. Ripple’s XRP cryptocurrency is touted as the fastest blockchain available today; however payments are centralized among a number of nodes, and gambling transactions may become censored in the future. IOTA also claims fee-less transactions, however each transaction requires “proof of work” to be carried out by the sender; costing a somewhat sizeable amount of electricity to complete.
Currently transactions sent on the Lightning network are free, however it is likely that small fees (fractions of a cent) will be implemented at a later stage.