I don't expect to get any money for work that I haven't done yet. I do not require advance payments (with one exception) and I won't ask to be paid for work that you don't find acceptable. However anything I write belongs exclusively to me until I transfer the rights to it; distribution rights are only transferred when I receive the agreed fee in full, and until then I retain full and unconditional copyright to the work. My rates start at $5 per 100 words plus Guru fee, so if you're offering less than that I won't be able to accept your invitation. I am also no longer accepting hourly-paid jobs.
The exception with advance payments is for sample articles. Sorry, but I've had too many people ask me to write a "sample" article then disappear without paying. I am happy to give you examples of my previous work, but if you do ask for a sample written on a topic you provide I require full payment in advance at a rate of $5 per 100 words. Please don't ask me to do any work for free; it's a violation of the terms of service, and I will report it.