The Element app is free. When it comes to choosing where to host your data (your conversations), and extras such as bridging, there are free and paid options.
Free hosting
Self-host or use a free public server.
Free bridging services
Manage your own bridging using open source options.
The Element app includes
Unlimited end-to-end encrypted messages
Unlimited voice and video
Choose where to keep your data to protect against data mining and adverts
Interoperability with other Matrix-based apps
No bridging included, but available via open source