I've been doing this for 17 years, and use various freelance sites occasionally when my guys can't get something done or we need more hands for ASAP turn around.
It depends drastically where you shop (ie: which country).
$10-$100/hr for php and python devs that are GOOD, know GOOD ENGLISH, and know wtf they're doing. I know some people who hire the CHEAPEST outsourced labor 4-8$hr devs for projects that just need to "WORK" to turn a profit. So, it really depends on your needs too.
If you don't have an experienced developer managing the "cheap" freelancers they are, imho, not really wroth it due to the corrections needed more often than not. It would seem many developers learn the "technical" side but don't study any of the "why" so while they can do Task A, asking them for their input/thoughts/opinions etc is hard to find, and this is even more-so in Asian cultures/countries. I don't mean to stereotype but they're just less likely to state their opinion, even airline studies found this doing crash studies.
With that said there are what I call 2 types of developers. Those who love it, do it, live it and continue to grow. Those who like it, but only learn the technical part, and when their day-job is over they're washing their hands of code to never think of it until the next work day. You hire what you need based on who's managing them, and how good you are at writing project specifications.
I find $25-35 will get you someone in the US who's mid-level. I've paid up to 100/hr for very experienced developers, they're normally 2-3x as fast, and have a brain that can solve problems.
Again, unless this is your field you really are going to have a hard time, and could cost more in long run vs local hire. You could have someone help you hire based on your needs or use one of the many 3rd-party out sourcing agencies for help. They're popping up all over last few years.
FWIW: I like to give my dev. applicants a "test" with 3 questions. They're technical but also shows their problem solving abilities and how they code to solve the issue which reveals their thought process and style of coding.
Hope that helps.
Depending on what you need too, I'd gladly bid the project.