It doesn’t cost much to just launch a cryptocurrency.
It can be as simple as deploying a smart contract on
Ethereum or any other blockchain platform.
Or, you can just fork an existing cryptocurrency to create your own version with a different name. Most cryptocurrencies are open source anyway.
Here’s a quick guide on how to launch a cryptocurrency on there -
How To Create Your Own Ethereum Token In An Hour (ERC20 + Verified) — Steemit
According to the post, it cost him about ~$30 USD to launch the token. So, that’s the rough estimation.