Demand, supply and finance are the three major factors governing collection development. Both demand and supply will be increasing while finance will be always inadequate. If mind is to be fully satisfied, a library will have to buy more and more items. This is particularly so since more items are being published everyday. New items published will naturally stimulate more reading and in turn place more demands upon the library. In order to meet growing pressures of demand, funds at the command of the library also ought to grow. But, generally, this does not happen. On the country, library budgets are very often subjected to severe cuts on account of other priority allocations. Even in cases where funds remain static, the purchasing power of the available money may go down due to inflationary trends. To make matters worse, the prices of reading materials have always a rising trend. The ultimate result of this conflict of factors is that the library will not be able to buy all that it should. This is the case with even the richest library in the world. Therefore, you must know how to utilise the available money in the most judicious manner. As advised by Mellvile Dewey, your motto must be "the Best Reading for the Largest Number at the Least Cost". The principle under the balancing of the three conflicting factors - books, readers and money. You have to ensure that the funds are expended in a such a manner as to build up a well-balanced purposive library collection. Strict financial discipline, therefore, is needed in acquisition work. A tool which will help you in observing this financial discipline and in ensuring a balanced growth of the collection is the budget allocation.