While folks (particular Jason) are giving you excellent advice, can I take this from another angle? A $20 bill rate does not mean you are getting $20 per hour. Not even close. You have to factor in all the non-billable parts of consulting, like writing proposals, educating these clients that $10/hr providers will likely not lead to project success, and handholding them through the project because they'll likely need lots of it. They're disproportionately likely to be pathological clients because they are attempting to do business in a place which might as well be marketforlemons.com to save a few hundred bucks. It took me years to adjust to this, but it is true: a few hundred bucks is not a lot of money.
Can I strongly suggest you make a small investment in improving your business skills, get clients in the old- or new-fashioned ways without a marketplace site, and laugh in the general direction of a $20 bill rate? Also, don't call yourself a freelance programmer. You solve problems for businesses. Many businesses have problems such that there is no number they will not pay to get them resolved.
I'm not sure if you've done this in the past, but would you mind explaining how to get clients in the "old - or new-fashioned ways without a marketplace site"?
You network. You build relationships. You go to meetups and meet interesting people, swap connections, swap leads. You get strong introductions, you follow up, you build client relationships. They like you, they trust you, they want to do business with you, and they're willing to pay 4 or 5 figure sums for the privilege because you sell them more than work: you sell them peace of mind.
http://swombat.com/2011/2/25/kevin-mcdonagh-how-to-attend-a-... also proposes an approach to get leads from conferences (and despite the apparent machine-gun methodology, I'd like to qualify this article by saying that Kevin is an incredibly chilled out, laid back, friendly kind of guy).
All of the above, plus building an online presence in your area of choice. It is both a good way to make weak ties that turn into strong ties, and a good way for folks to find you when you're not actively networking.
Blogging and community participation (HN, etc) is my best source of consulting leads next to personal recommendations (and it is often a friendcatcher which caught the person doing the recommending).
"you sell them more than work: you sell them peace of mind."
This is the key to freelancing in general, as my father always tells me.(freelance photographer in the Middle East for almost 40 years: http://gustavoferrari.com/).
Whether it's online or off, if you can convince your clients that you can get the job DONE, with no excuses or delays, they will come back again and again. They want to be able to send you work, and forget about it, confident that you will come through.
Currently the shortest path that I can see is to go deep into iOS or Android programming, write a program or two, publish them in the respective app store, build a basic website to promote yourself (i.e. make an online portfolio i.e. just describe the programs you wrote).
Then go after iOS and Android gigs. Currently demand is vastly greater than supply and both platforms are growing, so it's likely to be true for some time.
The "market for lemons" paper was not about the average quality of the market---it was about the selection effects generated when market participants cannot judge quality. Within a online labor market, there are platform-imposed features that reduce information asymmetries & make relative comparisons possible e.g., tests, feedback, verified records of billed hours. The informational problem is much worse without an intermediary, which is why these markets exist.
I agree with everything you say, but still believe that these sites are markets for lemons. The information asymmetries are still severe enough to compromise the overall utility of the market. (If they weren't, this thread would not exist.)
Can I strongly suggest you make a small investment in improving your business skills, get clients in the old- or new-fashioned ways without a marketplace site, and laugh in the general direction of a $20 bill rate? Also, don't call yourself a freelance programmer. You solve problems for businesses. Many businesses have problems such that there is no number they will not pay to get them resolved.