I been thought of this for some time.
First, producing online video content required at least a video camera, that could take at least HD resolution. Because this is the trend going forward.
Furthermore, if you want your video quality to look nice, you need at least semi-professional light.
Another item you need, the software tools. You can use freeware for sure. But the better and more flexible software like Adobe Premier isn't cheap.
After you finish all, you need a high speed broadband to upload your file, which could probably over GB for a HD version.
All these, will cost you at least $5,000.
Compare to writing online, you only need a later + broadband + creativity.