Market cap and trading volume explained in three sentences:
24-hour trading volume is the total value traded over the past 24 hours, reflecting how active buying and selling have been during that period.
The price of a low-market-cap coin can be easily affected by a single large order, so its price swings are usually more dramatic; market cap does not indicate whether a project is good or bad.
Judging whether a coin is “cheap” based only on its price is not very meaningful—you should also consider its circulating supply and market cap.
$BTC 82850.26(+0.058%)

Just a note, not investment advice.