The price system motivates Gus to purchase the equipment for the chemistry lab, hire the resources needed and take the risk to produce and distribute the methamphetamine. Gale is shocked by the investment, but profit motives are often used as the incentive for investments. Firms only invest in resources if they believe they can lower the cost of production (given a fixed output) or to increase production either of which would increase profits.
See more: capital, economies of scale, elasticity of supply, fixed costs, incentives, inputs, investment, invisible hand, production, profit, profit maximization, variable costs