I have an ice cream maker and I love it. The thing is you have to kind of...shift your thinking with it a bit. Compared to what you buy in store, what you make at home (at least with my machine) is quite a bit denser. You can eat less of it and still feel full. If I were to pour what I make into a store bought ice cream container, it'd weigh more and I'd get more servings out of it because you just need less when you actually eat it. I also find what I make at home has a lot more flavor, again sort of negating the need to eat a lot of it.
So that all being said, it does cost more to make it than it would be to buy a big name brand. It's less expensive to make than the fancy little brands that cost like $4 for a pint. It just really depends what you put into it. Putting fresh fruit into the ice cream costs a fortune, but it's just sooo much better than what you get in the store. Making it, you can control the ingredients where there's not going to be those methylhexachromate dimonoxygen type chemicals.
It's really a crapshoot as to what you see as what it's worth. If you want a denser, more flavorful product that you can control, and don't mind spending the time to make it? It's great. If you want something that doesn't take a long time to make and is quick and accessible, just keep buying it.