Final answer:
The general rule for pricing over-the-counter items such as cost-based pricing, where prices are based on production costs and profit margins, as well as other methods like competitive and value-based pricing. These are influenced by market forces of supply and demand.
Step-by-step explanation:
The general rule of thumb for pricing over-the-counter items is often cost-based pricing, which refers to setting prices based on the costs of producing an item plus a fair profit margin. However, other pricing strategies also play significant roles, such as competitive pricing, which considers the prices of similar products in the market, and value-based pricing, which is determined by how much customers believe a product is worth.
It is also crucial to understand that prices in a market economy are affected by supply and demand, which tend to drive prices to a point where the quantity supplied equals the quantity demanded, known as equilibrium. Efficient allocation of resources occurs when the value to consumers of the last unit bought and sold in the market equals the marginal cost of producing it, as suggested in point 3.5. This concept is derived from what would occur in a perfectly competitive market.