Political science and economics are social sciences. Political science is the study of politics in theory and practice, while economics is the study of how resources are produced, allocated, and distributed. As well as dealing with subjects that often relate to one another in everyday life, the two are commonly seen as sister subjects in academic terms.
A variety of topics related to politics are addressed by political science. This includes differing political philosophies about how society should operate. It also includes the way political systems work to produce laws and government.
Economics deals with two main areas. Microeconomics is the study of how individual consumers and businesses make production, purchasing, investment, and saving choices. Macroeconomics looks at how an entire economy works and the way policies can affect the combined effects of microeconomic decisions. It can be argued that economics is a social science rather than a pure science, because it is based around resolving an irresolvable dilemma: how to meet people's unlimited wants with limited resources.
The most prominent link between political science and economics is in the practicalities of government. For example, there may be a connection between whether a politician considers himself left-wing or right-wing, within the context of the country concerned, and whether the politician puts more weight into fiscal economics, which aims to stimulate the economy through government spending, or monetarist economics, which aims to stimulate the economy by influencing the price and availability of credit. There are many topics in which stances can have both a political and economic element, such as whether a government should attempt to reduce inequalities across society, work towards equalities of opportunity, or avoid any interference wherever possible. Taken as a whole, political and economic views can't always be simplified into two camps; for example, some politicians consider themselves economically conservative but socially liberal.
One of the most common crossovers between these social sciences is rational choice theory. This is the study of, and attempt to model, the ways in which individuals make choices. It could be argued that rational choice theory is an economic theory that is contradicted by political reality that is harder to objectify. For example, an economist would use rational choice theory in assuming that a consumer will always choose the cheapest supplier among those offering identical goods. Politics might explain why some consumers will instead choose to pay a higher price to get the goods from what they see as a more ethical supplier.