Id repot them in a bag of potting compost from your local garden centre - its dirt cheap (no pun intended) and works great for my plants (the magical variey, if you get my drift). Works out at about a fiver/$10 for a massive bag, not sure how much is in there though. Perlite is a must aswell I find, for all plants.
The potting compost contains all the essential nutrients that you need, and you only need to start adding fertiliser after around a month.