ODesk is the least bad of the general sites. There are a few niche networks that are decent also, e.g. TopTal.com.

I agree. Odesk is decent.

My experiences with Freelancer.com were awful:

https://news.ycombinator.com/item?id=5177951

Does anybody have any experience with TopTal? Somebody (I guess a recruiter had just sent me an email inviting me there?)

I have worked with both elance and odesk. I shifted to Odesk after some issue with elance and never looked back.

What went wrong with Elance?

Without being rude, what sort of income is possible from those sites?

It's tough. Personally I know that I severely undervalued myself but it allowed me to work via email and not have to interact on the phone or in person with people which I had trouble with for a few years. I was able to make enough money to 'get by' In other words I just about covered my basic living costs for a small city in the UK. We're talking about £800-1300 per month which was fine as a single college aged guy. Eventually I got a few long term clients from those sites (I've been working with one guy for 3 years now) who I gradually raised my prices with until I was valuing myself fairly. I've moved off them completely now and am working in a startup which I much prefer (although I've kept on that one long-term client as the work is easy and he's easy to work with). I've lost the tremendous freedom freelance work gave me which I'm finding difficult but I don't have to stress about where my paycheck is coming from.

Thanks for your honesty.

When you say you undervalued yourself, what was the rate you were charging on freelancer?

I charged a price for the whole project. At the end of the day it probably worked out to $10 per hour. I started this when I was 18 so imposter syndrome was a big deal for me but over the next few years I gradually increased prices. At the end of the day though if I had bills I needed to pay I would take whatever work I could get and sometimes that meant bidding lower than the other guys. Eventually I got better at selling myself and convincing people that although I charged more than other bidders I was worth more. I think my biggest mistake as a freelancer was not charging hourly. I screwed myself quite a lot taking on projects that ended up being WAY more work that I thought.

I know a few hundred dollars here and there doesn't sound like a lot, but if you are doing it while living in a country with a favorable exchange rate (say, Brazil or Argentina), it becomes an easy way to earn a decent living. I've done it myself.

Even with favorable exchange rates, living in most metropolitan areas in Brazil is very expensive and you are likely to earn more working for Brazilian clients - right now unemployment is under 4% in general and almost inexistent in IT so wages are up.

The situation in Argentina is good if you get paid in cash because the black market pays twice the official (and artificial) rate. I guess it is not so good if you are being paid through a prepaid card like payoneer.

I assume you mean PPP ratio.

While PPP is probably most important exchange rates matter too. Most people tend to bid/pay in USD. So for me when the GBP/USD was right I could charge the same as usual in USD but that translated to more money in GBP.