I may be wrong but I think most people who make money on CL or Ebay are not making enough money to sustain a family. Exception could be Ebay if they are reputable, have a store and a lot of time to spend on it.
I have tried to sell some things on Ebay (daughter's clothing) unsuccessfully. There are charges involved with placing ads and buying products. I have heard that some people are really savvy about it but it takes time and a lot of effort. My stuff is still in the closet.
CL is iffy. Most of the time it is people who have popular items (latest tech toys, tickets, etc) which are hard to find in stores and they make money off of those items here and there. Prime example....I was looking for a hard to find Wii Guitar Hero Band Kit which retails about $190. They are sold out everywhere....I placed a want to buy ad on CL.....within minutes.....I was was hit with emails with people trying to sell me a new one for $500+. Lucky for me, my persistance with checking stores regularly led me to one of the sets yesterday at regular price. I refuse to be scalped on things like that....
HOWEVER, When we bought the hard to find Wii back when it came out almost 2 yrs ago, we did get it on CL and paid retail plus tax for it from someone who had purchased 2 by accident. His wife found one same day he did so they ended up with 2 and they just wanted their money back. That RARELY happens.
That is just my experience with the 2 sites.
I also would steer from companies (agents) who approach you to "sign up" to represent their product. When you make an investment to be a sales rep (own your own company), you are making money for the person who signed you up (EX: MLM's). Granted, not ALL Mlm's are bad but most are very high pressure.
Good luck to you!