The struggle in the economy and on the field
In the market there is always competition between the buyer and the seller. The buyers and sellers goals are getting the better/lower good and services. In the game of capitalism the buyers and sellers struggle to get the best price for the product.
Stack of money
Capitalism is based around money, you don't have money you don't have an economy. Prices are determined by supply and demand that are determined in the marketplace to buy products. You use money to pay the price, make the goods, and sell the goods; money answers the three economic questions.