多少【duōshao】

多少 asks "how many" or "how much" with no ceiling on the answer.

The measure word is optional

Unlike 几, 多少 can go straight onto the noun. Adding the measure word is also correct and slightly more precise.

多少 against 几

几 expects a small number and always takes a measure word; 多少 expects anything. Asking 你有多少个哥哥 sounds like the family is enormous.

Prices, phone numbers, dates

多少钱 is the standard way to ask a price. Numbers read out digit by digit also take 多少.

多少 in a statement

Without a question, 多少 means "however much" or "some amount".