Chord ai is free to download and use in its basic version. Within Chord ai, you can unlock pro features through a subscription to Chord ai Pro. 

Chord ai Pro provides either a monthly-based or yearly-based subscription. The price depends on your App Store country. For instance, in the US, Canada, Japan, Western Europe, the monthly price is ~9 EUR/USD monthly  or 69 EUR/USD yearly. In other countries, the app is generally a little cheaper.