A comment could potentially make hundreds or even thousands of dollars but that it very, very unusual. I can't recall seeing one make more than a few hundred dollars and even that is very rare. Most users will use the majority of their voting power to vote on an article rather than a comment.
When you're a minnow and trying to build up your steem power you save your votes for articles and not use them on comments. Unless you really like it of course. Over time as your account grows you will one day see a slider appear when you vote. That allows to determine what % of your voting power that you want to use. At the moment you are voting at 100% every time that you vote so use it wisely.
There is a minnow support group that you join on the Discord app and you'll get lot's of answers and support in there. You can also use the search function at the top your homepage to search for answers to your questions. A number of really good starters guides have been written but I can't recall their names - go on a hunt them and you will soon find them.
Here is a link to the minnow support group - https://discord.gg/BxDfcmd
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