My short stories are all romances, so you can take this advice with a pinch of salt.
It's perfectly reasonable to self publish short stories, and it does not imply that they weren't good enough for literary magazines. There is a finite number of literary magazines with a finite number of stories in each. I would venture to suggest that the supply of excellent stories might easily exceed the demand for them in literary magazines. And the readership of literary magazines is certainly smaller than the potential readership for a self-published story (though possibly larger than the actual readership). Self-publishing is riskier, because it's a business venture, but the rewards can be much greater. My best-selling short story has earned several thousands of dollars, much more than any magazine would pay.
I would say that bundling two or three short stories is probably a good idea, but I would also recommend that you don't under-price your work. People will assume it's not worth much if you only charge 99c for it. For a small bundle, I would charge at least $2.99, and if the stories are very short, I'd add in an extra story rather than lower the price. You want the $2.99 price for the sake of the 70% royalty. Get a great, professionally made cover and get professional editing. You're aiming for a product that is indistinguishable from something a publishing house would put out.
The other thing you can do with short stories that might be worth considering is enrolling them in Kindle Select so that you can take advantage of the Kindle Unlimited scheme. If you do this, I would publish the individual stories in Select, and then as a bundle which is not in Select (but is still only available on Amazon, so as not to violate the TOS). The reason for doing this is that KU subscribers can borrow the individual stories as part of their subscription package, and you get paid for each borrow (currently about $1.40 per borrow, regardless of the length of the book or its price). Put good back matter in each book, directing readers to your other work and you can build up a core readership.
The readership for short stories is never going to be as big as for full-length novels, but it does exist and a lot of ebook readers really like short works. I say, go for it.