That is truly a vague question, as for the most part the pricing depends on the quality of work and the current experience, a price comparison between in-house and outsourced would make sense, but for the most part dont compromise on quality!
You will find a tad bit of a difference between countries, but more often than not remember to factor in confidentiality, service, etc. into the mix, furthermore in my experience when hiring cheaper labour the end cost, is usually the same, i.e. an expert requires lesser time to figure things out, write the code, fix bugs etc.
There are Central and Eastern Europe country outsourcing profiles http://itonews.eu/outsourcing-analytics/cee-country-outsourcing-profiles/page/2/
Our expericne is to not just compare hourly rates. There are soft or hidden costs. If you are a USA firm and looking to far offshore (Asia, Eastern Euro), then consider the cost of travel for both parties, visa's, and the cost of productivity loss with time zones, language, culture, fatigue, frustration, etc. Off shore is never going away, but there is a strong trend to leverage resources closer to USA from rural centers in the USA to nearshore as in LATAM. Our firm is US based but most of our bilingual staff is in Mexico. We are setting growth records so something must be right. If you are using an Agile SDLC, take a close look at doing so from offshore vs nearshore.
I used Elance.com for a project and had pretty good results (I chose a provider in Portland who wasn't the cheapest but sounded like they knew what they were doing). I have also heard good things about oDesk.com.
You may find not just hourly rates, but a lot of other country-specific information in a book called "Software Without Borders " written by Steve Mezak.
Rates vary greatly not just by country, but also by skill set, e.g. PHP coding vs. GPGPU programming, by whether domain knowledge is required, and so on.
As for Elance, RentACoder, and just about any other outsourcing brokerage site, most of the providers either do not have a clue, or have not gained reputation yet, so their rates are way lower than those of the best providers. I would therefore limit my research to the top 5-10% of all providers by rating, number of projects completed, and amount of money earned.
I did this analysis of software developer salaries across the world https://www.staff.com/blog/web-developer-salaries-infographic/ But essentially I can summarize it like this from the major offshore locations where you can potentially outsource to. The Philippines, India, and former Soviet Union are the 3 major blocks of countries where you can outsource. Of course there are many others (Pakistan, Sri Lanka, Vietnam ... the list goes on), but these 3 cover a very large percentage of the available English speaking talent.
Philippines - lowest cost
India - slightly higher cost
Former soviet union - higher cost still
And of course, Western Europe, the US, Australia, Canada - highest cost
The cost will then depend on many factors such as if you are hiring an individual person or a company (I suggest an individual and that's the only way we do it on Staff.com
Pricing should not be the only criteria. You get what you pay for, the best is to look for a great track record of any development company