Yes, and at a higher rate than typical data, because it bypasses the compression built into the (gateway?) system. Literally EVERYTHING you do online uses data, and countless things your devices do on your behalf with or without your knowledge. If you can't do it without your modem turned on, it uses data.
If you use free vpn that means your are giving your data to them. Because free vpns are data caps and they keep logs. Better to use any paid and reliable VPN to get secure and anonymous connection without any logging. Check out bestvpnprovider.com for paid vpn providers.