Simple R language prediction model

I need simple program written in R programming language regarding prediction models. What I need to do is to prepare estimation model for electrical power distributor who is buying power in regard to contracts within some timeframe (for example: a month, a quater, a year etc.). Following contracts most likely lead to power surplus or deficit due to distributor's customers needs. When it happens we shall take actions to decide whether we buy or sell power to one of two sample companies. Price level on those companies may vary so we need to make decision what action we should take, and to which company we should sell or to buy from to optimize distributor's income or minimalize loss. Final decision should be with which company we shall operate. Training data for the model will be provided, as well as validation data.