The short answer is: Yes it would save money to make multiple starters from a single vial of yeast.
Now, the long answer: Yeast starters work best when they're not too large, or too small. If you have one vial or smack pack, you have about 100b cells. The sizes of starters that will make the most healthy growth is going to be between 1.5L and 4L, with 2L having the best yield factor. If the starter is smaller than 1.5L, you won't make hardly any new yeast. If the starter is too big, you'll mostly make beer, instead of as many new yeast as possible. So you should pitch 100b cells per 2L of starter.
I would make a 2L starter from one vial. You'll roughly double your yeast, to about 200b. So now you grew another vial's worth of yeast. You could split that in half and use one half for your beer (assuming you only need 1 vial), and save the rest, or you could save half and pitch the other half into another 2L starter.
Just dividing a single vial into 3 starters would be fine, if you follow the same 100b/2L rule. Each starter would have to be 0.66, which is pretty small, meaning that for each of those starters would make about 2/3rds of a vial. 1 vial is sometimes enough to pitch into your wort, but 2/3rds of a vial is very seldom enough yeast to do so. So you'd have to make at least one larger starter out of each of those 3 starters when you want to use it, and you might need to step the starter up again depending on the gravity. That is more hassle than I'd want.
Each time you make a starter you risk infection. Bacteria will reproduce about 100x faster than yeast, so a very small infection in your starter could become a very large infection in your beer. Sanitation is much more important when making starters than when making beer.