Another method you might consider is milestone based payment. You have a project-as-a-whole cost but have set milestones and when they are met you get paid. This is nice for both parties at the beginning of a relationship to "test the waters". If they flake out on you, you aren't out as much time. They also have less risk.
You can get creative with how it is broken up as well. I've taken the approach before of having the first few milestones be less expensive to get a foothold and get them "hooked" on my skills. At the same time, I am evaluating them on communication, requirements, and how we work together.
FYI: Retainer based pay is usually a hard sell to make but once they do it, they love it. I have yet to have a client not want to do it after we have started down the path. However, I have had several potentials deny me outright. Since I do freelancing part time this is okay by me. I really favor long term/large clients. The hustle of getting clients is annoying to me. I'd rather give a decent discount (e.g. 35k vs 60k) for a client who knows they will use a whole month of my time (all I do per year). When I did the cost analysis, it was about even. However, I'd rather be coding than marketing another client.
I second the milestones idea. I used to do this back when I was freelance web developing and it helps the client feel more comfortable knowing they're paying as they see progress. (Helps you a ton too cuz you get money as you go along).
This was one of the major features of my new startup matchist (http://matchist.com/talent). You create milestones for your client and they prefund each milestone before you start working on it. Once you're done, we release the payment to you.
You can get creative with how it is broken up as well. I've taken the approach before of having the first few milestones be less expensive to get a foothold and get them "hooked" on my skills. At the same time, I am evaluating them on communication, requirements, and how we work together.
FYI: Retainer based pay is usually a hard sell to make but once they do it, they love it. I have yet to have a client not want to do it after we have started down the path. However, I have had several potentials deny me outright. Since I do freelancing part time this is okay by me. I really favor long term/large clients. The hustle of getting clients is annoying to me. I'd rather give a decent discount (e.g. 35k vs 60k) for a client who knows they will use a whole month of my time (all I do per year). When I did the cost analysis, it was about even. However, I'd rather be coding than marketing another client.