Cheap and easy: buy a 2 TB drive and keep it at home. If some disaster affects your home -- flood, fire, burglary -- it can take out your data and its backup.
Cheap and reliable: buy a 2 TB hard drive and keep it somewhere else. Keeping the backup up-to-date means regularly bringing the drove home, updating it, and putting it back.
Easy and reliable: pay for a service like Backblaze that automatically backs up all your files to a remote server.
There are other benefits to services like B2 especially, namely being able to access your backed-up files from any device or location, or being able to link people to your files on a high-speed server.