The Commercial Rating will allow accepting compensation for flying. Like most things in flying, it isn’t always that simple. However it is the step where you get to start getting paid for some services.
Many people find the commercial is a fun rating to complete. While it is challenging, it does not have to take a long time to complete.
The minimum is a total of 250 hours of flight time, and 20 hours of training toward the rating. However, many times between getting a private license, perhaps getting an IFR rating, and completing the 250 total hours a pilot has completed several if not most of these requirements.
Sometimes all that is required is to brush up on old maneuvers, learn the new maneuvers, and possibly complete a couple requirements missing. 20 hours of plane and instruction is generally a good number to budget for. Like any rating, the amount of times you can fly and study per week, as well as the amount of flying you have done recently directly impact the amount of hours required.