I get asked this question all the time! Now there is this handy dandy info graphic to help you do some calculating. Check it out!
It looks to me like these prices might be a bit low. It’s always a sliding scale depending on the quality and location of your programers. You can always get a less experienced programmer cheaper, but you may end up spending more in de-bugging.
You may be able to get an overseas programmer cheaper, but you may have communications issues, and a slower delivery.
Basically it’s all a trade off based on what is most important to your particular project.
If you want more detailed info, I’m happy to hep you craft your scope of work to get the right team hired! Give me a ring 713 478-4018.