When a client buys a video from you, you will have to deliver that to them. Using email to send large files to your clients can cause problems at both ends. So it's best to use a tool that allows large files to be sent.
Below are list of some free tools that allow large files to be sent smoothly. Check them out if it's what you need. You can also do a google search for other tools available.
1. Infinit - https://infinit.io/ = Send files and folders of any size or format from a complete photo collection to a HD movie.
2. we transfer - http://www.wetransfer.com/ = sends up to 10gb
3. itrnsfr - https://itrnsfr.com/ = sends files up to 2gb
4. Sendspace - http://www.sendspace.com/ = With the Sendspace app, you can send large files on the move
5. Dropbox - http://dropbox.com/ = well known way to send large files.
6. Mediafire - http://mediafire.com/ = sends large files up to 100MB