Well it depends on legitimate. If you are not willing to risk any of your own money, then blogging, writing(like hub Pages), affiliate marketing are some ideas that pop into my mind. Are you going to quit your job a month into these ventures? No. but could they, if you worked hard enough add a significant income stream or replace your normal job years down the road? Probably.
If you have some funds to put to work, I trade currency futures and dabble in binary options. its risky, takes a lot of learning, and experience controlling emotions, but I have made a small amount of money from them. it's not steady or predictable, but I am in the black on both of these areas.
I think there is stigma surrounding working online. Making a living online will take just as much, if not a ton more effort than a normal job starting out. You will have difficulties, setbacks and failures. But if you think long term, or just to add a small amount of extra income to your current situation, then put your nose to the ground and work hard and like most other things, the harder you work, the more likely you are to succeed. The problem is people want an easy fix and call everything online a scam if they do not become millionaires instantly.
Again, working from home or online has tremendous perks, but the road to get there is hard, and a lot harder than working for someone or having a "normal" job.
Hope that helps.