I lot of long distance cyclists I know use ENDUROLYTES
80mg Sodium (as Sodium Chloride)
120mg Chloride (as Sodium Chloride)
100mg Calcium (as Chelate)
50mg Magnesium (as Chelate)
50mg Potassium (as Chelate)
0.5mg Manganese (as Chelate)
Doesn't seem like it would be too hard to mix up something similar for a lot less than 40¢ a dose. I prefer Fritos or a pickle.