I'm working as an artist/illustrator, and one of the things I picked up along the way is, that you can make great work with even the cheapest tools. No need to pay a fortune for high end stuff, although they might last a little longer (ink is gonna kill any brush real quick anyways). I just try to register how everything works together - how the ink, water, colors react to each other, how they flow on the paper etc. - and adapt my process accordingly. I rarely fuck things up beyond repair.
For lines, I use a nib pen. No idea what brand and size, though. If I want a thick line, I'll just add more pressure. It's not one of those broad caligraphy ones though!
For shading, I use two brushes; a kinda big one for the ink and a kinda small one for spit/water. No idea what brands or sizes, though - but the were cheap.
For colors, I use Ecolines. In my oppinion, they suck straight out of the bottle - way to bright for me, but they're easy to break, so I just mix them on a plate.
I'm using 300g watercolor paper. No idea what brand, but it was cheap.