Mark Taro Holmes, an Urban Sketcher and a very good one, recently shared his tools in an interview and made a few excellent points:
About the paint:
1) try the paints out in smaller size tubes until you know you "really like" the colour.
I so wish I had been given this advice years ago when I started to paint with watercolour because now I have a huge collection of paint that will undoubtedly not get used.
About the paint brushes:
He says, and I often agree, that synthetics can be as good as the best sable.
My favourite synthetics these days are the Lowes Cornell 7020 & Utrecht's 228 sabettes.
Both these synthetics hold a good point, are easy on the hand and inexpensive.