The surface is the most important tool for watercolor because watercolor is a transparent medium in which texture of the surface is clearly visible. In fact it plays very important role in painting.
Also the paper should be chosen wisely as the surface of the paper may peel off with excess use of water. It is advised to use paper made of 100 % cotton pulp, with no wood pulp and acid free for better quality.
There are three types of papers existing in market that is rough, cold pressed and hot pressed which are available in various thicknesses. To begin with one can use cold pressed paper, as it is more flexible to use.
These papers are easily available in nearby stationary shop and the cost depends on the quality and thickness or weight of the paper. Heavy weighted paper can take more applications of water and paint as well as scrapping and scrubbing.