Final answer:
Goods with many close substitutes usually have lower prices due to increased competition. Shifts in tastes, populations, income levels, and the prices of substitutes can directly influence the demand and prices for these goods.
Step-by-step explanation:
Goods with many close substitutes tend to have lower prices. This is because the presence of substitutes increases competition among the sellers. If a taste shift to lesser popularity occurs, or the population likely to buy drops, or if there is an income drop for a normal good—which means the good is purchased more when consumers' income increases—or the price of substitutes falls, the original good’s demand decreases, thus pushing the prices lower to compete.
Conversely, if there's a taste shift to greater popularity, or the population likely to buy rises, or income rises for a normal good, or the price of substitutes rises, it can lead to higher demand and potentially higher prices for the good, as consumers will have fewer equivalent options and a greater desire or financial ability to purchase the good.