This is a job that will vary depending on where you work. Let's not pretend like a small bar in the middle of the mountains in Mississippi is going to make the same money that a bar in downtown Los Angeles does, especially if they serve twenty seven dollar drinks. There's that to consider, but its a job that doesn't require any specialized skill other than making drinks. Although no degree is required, there are some barrier to entry with this career.
There are bartending schools that will teach you how to bartend and also find you job placement, but there's no guarantee, and like a degree, you're basically paying for the education. The costs are very low, though they are something to consider. Many bartenders have gotten jobs in the industry without attending a bartending school, so fret not if that's not an option you'd want to pursue.