PENCIL:
the good 'ol #2 pencil is an artists best friend. yes, the one and only. although there are many different kinds of leads, varying in hardness and type, the #2 never fails to get the job done.
PAPER:
having a good sketchbook and a few brushes is key if you plan on using watercolor. Whether the paper is cold pressed or is on the thicker side, this will effect the way the color appears and is absorbed. a favorite of mine has always been the canson coldpressed watercolor paper.
WATERCOLORS:
the winsor and newton watercolor set is affordable and you can purchase it at a discounted price if ordered online. the colors are absolutely beautiful and absorb into the paper very well.
BRUSHES:
I would suggest investing in some nice brushes if you plan on painting quite often. I use the master's touch synthetic brushes. they have a good variety to choose from and the bristles don't fall out. I've had mine for a few years now and they are still going strong.