A lot depends on whether you want to build your own optics, or just to assemble the optics into a tube. Grinding lenses is not for beginners; I'd definitely recommend that you purchase your lenses from supply. Grinding a mirror is easier, especially with hands-on help, but you can also buy a decent mirror.
A Galilean refractor is an odd choice. It does present an upright image--a plus to many beginners--but it provides inferior image quality and a narrower field of view compared to the more typical Keplerian refractor. The Keplerian refractor does invert the field of view, but in astronomy, there is no up or down, so inversion doesn't matter a whole lot. If you're following star charts, just turn the charts upside-down.
The Newtonian reflector is reasonably straightforward to build, and is one of the most popular designs going, both to build and to buy. It's an outstanding value either way.
I will reiterate what others have said, though: The reason to embark on this project is not to save money, because you'll probably spend just as much money putting the telescope together as it would have cost to buy it. The reason is to learn more about how telescopes are constructed, and to take pride in your work.
If you say a bit more about how much of the telescope you want to build, and where you live (generally speaking--no specifics), it would be easier to help you.