String "format"?

Hi!

Instead of "formatting" a string like this:

 string info = name + "costs" + price + " $";

I remember some time ago I came across a string, that looked something like this:

string info = "{0} costs {1} $"; (where {0} was a string and {1} was a float, and it became "Car costs 10 $")

If anyone understands what I'm talking about, how do you set this alternate way of doing it up?