Back then marketing was easier - just throw something up on eBay. But there are some 'hidden' costs not discussed.

I have a friend who did something similar back around the same time frame and he did pretty well. His niche was doing video tutorials on how to use new camera equipment. He needed to buy/own camera and video equipment. Luckily he already had it from is other endeavor as a photographer. He needed to have the skillset to the make and edit the video. Again, he had that from being a photographer. He ended up selling quite a lot of DVDs.

So the moral is to find a niche that leverages a lot of what you already have/know.