Cino is free to join.
You only pay when you use it.
There’s a €0.20 / £0.20 fee per split payment (per person),
which equals 25 payments per month, capped at €5 / £5 per person.
After that, you can keep paying together for free until the next month.
There might be a currency exchange fee when you spend with a non local currency. Check here for more on currency exchange fees.