Short stories are often dismissed by authors because they aren't "money makers." Ok, so maybe that's true to a certain extent. Chances are pretty slim that you'll be hauling in millions of dollars with them. Slimmer than the chance a novel has, at least.
But let's crunch some numbers, shall we?
The biggest advantage a short story author has is being able to publish new content a lot faster than an author that writes only novels. Say you publish one short story. It is reasonable to expect that that given enough time the short story will eventually sell one copy a day. Much of a short story's selling success is age dependent. My new stories almost never sell. My older stories sell on a somewhat regular basis.
So if you can get one story to sell one copy a day at 99 cents you've made about $10 that month if you're selling on Amazon. $10 is enough for Amazon to cut you a royalty check so don't sneer at the amount. That's money you didn't have before.
If you can get two stories to sell one copy every day, that's $20 a month. Remember, as a short story writer, you have the advantage of being able to put out quantity. Therefore, if you continue to produce work which, in turn, allows your older stories to age a bit, it's not unreasonable to eventually expect to have 30 stories that roughly sell one copy a day.
30 stories selling one copy a day is $300 every month. This is definitely not something to sneer at. $300 takes care of several bills or one car payment or a few nice dinners.