For the freelancers here:
do you guys ask hourly or fixed price?

Really depends on the project. For small Jobs hourly rate. For bigger projects fixed price.

Because in big projects you sometimes have to invest more in it to make it better. And defending why the extra hours are needed gets really annoying. And they are just trying to keep costs low. So most of the time shoot any extra work down. Leaving you with a product that could have been so much better.

Depends on the project. By going for a fixes price on site design, you can usually squeeze out a slight bit more money out of a project depending on your portfolio.

As for freelancing other programming tasks, especially systems languages, don't think twice about going for hourly payments! Those things can last forever...

Might be good to begin with hourly and as you get more experience estimating projects then do some fixed jobs.

As a freelancer, it depends. It depends on the person and their budget. But whenever possible, I charge per feature/component/module. I haven't heard of any freelancer doing that before. When I charge per feature, I also charge a 25% upfront (before any work is done) fee. If they argue or show signs of displeasure, I don't work with them, because I treat that as a sign that they could potentially not want to pay one or more other payments. If it's a small project, and I don't need to learn anything new and just know how it will be made, I charge a fixed fee. If it's small and I need to use something new or learn something new I charge hourly.