Are online job sites real or are they just scams?

I can say yes but you have to be extra careful as there's a lot of scam too. You need to search the net and browse over the websites, read forums and blogs. Take note of the sites that they will mention and read the comments. I can name a few websites where you can find legit work from home jobs. Craigslist.org is like a pool of job seekers. You need to pay a certain fee to be able to post. With elance and odesk you can either work as full time or part time and paid by the hour. But you have to bid for your rate. Of course, the lowest bidder usually gets considered. Last site which I highly recommend is https://www.staff.com./ Here you can work full time at a fixed rate. There's a lot of opportunities as well because there's a lot of job opening. Working from home is not as easy as you think. It requires skills and mastery of your craft and you must must be able to perform at minimum supervision.

The majority are scams! Don't waste your time and NEVER send anyone money for a job.

The case is there are different variants. It's better to consult with Google searching for comments on such sites. Personally I work for FreelancerCareers.com and am absolutely pleased.