I agree with all the points made above.
Most
SEO is mechanical work, but, the question you should asking yourself is, is the money you save worth your time?
I mean can you spend time in submitting links to directories, finding other related sites, emailing them about link exchange etc, or then writer articles yourself?
I think outsourcing is a great option, and the only way to see if the freelancer is any good is to ask for passed work.
Hope this helps,
Aditya