?4.99 a pop isn't cheap for these single strings, but elixir are by far the best guitar strings on the market! They last far longer than any other string, and never go rusty, so it's definitely worth buying elixir. I buy these single strings because if I break a string in a set, replacing it with a different string in a set of elixir will stand out a mile as an inferior string!
Elixir are by far the best guitar and mandolin strings there are! It's worth paying the extra on the long term even just from a financial point of view!