Wow! That's a great question! My husband is retired early and now cannot work due to suffering a stroke last July, and I really need to find a way to bring in a little extra money for some breathing space!
If you have some skills to offer, Freelancer, Elance and oDesk are sites for freelancers ranging from computer techies to grammar correction, copy-editing and even photographers. I found it helpful. It's difficult to start because no one knows you but once you get it going, you could get a decent income. Some hardcore freelancers do some odd jobs (because of their expertise) and rake in a few thousand for a project and then get off for a while until they run out of cash. I started getting into freelancing last year when I got married and finances got a bit tighter. For me, it was God's way of providing because even though I was new, I was given a couple of projects which paid double what the average freelancer would have gotten at that time.
In all things, trust Him who works all things for the good of those who love Him. He never forsakes and never forgets.
It is such a blessing that so many resources are arriving in this thread. Thank you all so much for sharing here. May God bless each and every one who is looking for extra income and happens upon these pages.
markethealth.com - (I spent 10 minutes on this one, then started getting checks in the mail. I forgot what I had done, and thought the checks I was getting were fake.
clickbank.com - You can make a good amount here, just gotta find something you're interested in.
fiverr.com - I know people who have made a good amount here.
sellhealth.com - affiliate type stuff
postloop.com - get paid to post comments on forums. I don't make anything here, but I do pay.
amonetize.com - made okay amount here, but only spent maybe an hour with it.