As you want to upload/download dummy (not sensitive data), you can use FREE options.
Free Fully managed / online FTP servers:
Some hosting companies provides “free” FTP server as part of their “free” plan. And so, all you need to do is create a free account, and have access to fully managed / online FTP servers with free FTP storage.
- ProFreeHost: seems to good to be true, but they promise unlimited bandwidth and storage
- BPlaced: nice option if you are German
- InfinityFree: also promise of unlimited space and bandwidth - but 10MB maximum file size
- ByetHost: free like a pro - 5GB worth of storage space, 10MB maximum file size, PHP, Mysql and more
- 000webhost: 300MB space, 3GB bandwith, PHP Mysql - advantage here it has no ads
Free Public SFTP Servers
But if you want to quickly test your SFTP client and don’t have your own SFTP server, try one of these publicly accessible SFTP servers:
Note: Most of them only allow read-only access. If you need to upload data as well, choose an SFTP server and download/install if yourself.
Free FTP server with anonymous access
An there are some companies that share publicly accessible FTP servers that allow anonymous access (you can connect to those even without any account at all)
Free FTP Server software:
A lot of companies also offer “Free” FTP Server software you can install on your own hardware.
- Filezilla FTP server: most popular
- PureFTPd
- ProFTPd
- vsFTPd
And as I said, there is really a lot of options.
More options
If you want to see a nice summary, go to Comparison of FTP server software packages - Wikipedia