Ah, thanks - you're half right :) The plan for Filecoin was initially (in 2014) to be based on Bitcoin, but since then this changed to its own Proof-of-Replication and Proof-of-Spacetime, reusing parts of Ethereum.

IPFS itself has never had any cryptocurrency integration, although there are external services that store your data on their IPFS nodes in exchange for Bitcoin.

(source: https://filecoin.io/blog/update-2017-q4/ and I'm on the IPFS team)