Generic drugs are cheaper than branded drugs because generic manufacturers do not incur the substantial research and development costs associated with bringing a new drug to market. When a company develops a new drug, they receive a patent that grants them exclusive rights to sell that drug for a period of time in order to recoup their investment costs. Metformin and metoprolol are examples of generic drugs that treat diabetes and hypertension, respectively, while Glucophage and Lopressor are the branded versions of those drugs.