It can be a tough business. There's people making money from free sites, the link pages of their own where they list them, the extra ads on such pages.. Their whole network of sites. I can see it in their stats, so I'm sure.
It's not just getting a free site to a link list though, it's building up from there.
There has to be a willingness to learn also, and attend the chats even if you think you know what you're doing and can do no wrong
The old "80/20/10" rule is in full force at all times. You can tell 10 people exactly what to do to make money, 8 wont do it for whatever reason (too hard, too much work, dont understand etc), 2 will try to apply it, and only 1 will succeed with it. So you have to be that 1 in 10 person and sprinkle on a little luck.
Try new things. Here's something that is a truism I guess.
"If you keep doing what you've always done, you'll keep getting what you've always gotten.".
So if you submit 10 freesites a week and get 1 sale a week and never change anything, then you'll get 1 sale a week for the rest of your life.
Try a new format, try a new sponsor, try a new site at your sponsor, try a new niche you've never tried before. Try a different content provider, try making your pics bigger. Try asking a link list owner what category gets the most raw hits. Try submitting to new link lists, try old link lists you never really tried. Try finding link lists with search engines. *ANYTHING* new!! Ever open photoshop to make a custom banner? Try it!!
You can most definitely make money from "just free sites" as long as that doesnt mean index, main, 2 galleries and submit. It's alot more than that.