I've had good experiences with something like "$90 first 30 hours, $60 thereafter". You have incentive to finish work fast because you want to start new projects to get the higher hourly rate, at the same time, the tail hourly rate means they won't be changing requirements too much.

When you must estimate a timeframe, make a honest estimate, and multiply it by 4.

I've heard it repeated quite often on HN, that if you want to make 100s of dollars per hour, you need to bid on projects instead of charging an hourly rate. The idea is that many people will spend x amount of money on a project without a second thought, where x will equal $200-500/hour when you figure out how long the project will take you to complete, but if you ask for an hourly rate that's three figures, they will generally turn you down.

I'm just a network security guy with aspirations of becoming a developer some day, but from my observation that seems to be the accepted theory with freelancers on HN.

Please understand I am writing this kindly -- the issue is that you are not an experienced enough freelancer.

You can compensate for this if you have the marketing and client management skills to get an aspirational rate, but if you don't, you need to be so good that you not only can see your way through a project in a conversation but see the potential traps and talk through them with the client confidently.

I believe that you can get this experience quickly -- good luck!

>They try to push for a flat rate, but I won't anymore because I have been burned many times by this.

Honestly if you're doing contracting then having a well defined contract should make this irrelevant. The burden of figuring out how long is on you, not them.