The way it works is the more money you have in your steem account the more money your upvotes pay. There are accounts that sell their upvotes. For example if I had 50,000 in my steem account and I upvoted you, you would get a few dollars. Most of us dont have a lot of money in steem yet so the people that do sell their upvotes to other people. For me the last few posts I paid to have a person with a lot of money in their account upvote my post.