You only need 3 or 4 brushes to start with. If you buy good ones and look after them they will last for years. The photo on the left shows well used brushes! ..a good selection. Note how well they still 'point' at the tip, even the large size 9.
When choosing your paper, make sure it IS watercolour paper, but it
doesn't have to be expensive for the early exercises. However, the thicker (heavier, not rougher) the better.
The photograph shows the huge range of texture available. You don't want very smooth or very rough to begin with.