Dr. Alex Harrison:
Here are some quarantine-friendly, money-saving tips for endurance athletes!
Flavor with whatever beverage you typically use. Saves big $$$$, keeps flavor mild, and moves sugar composition closer to 1:1 glucose:fructose, which is probably more ideal than the 2:1 or worse that is in most drink mixes.
Cheapest Gatorade: $1 / 200g carbs.
Average sugar price: ~$0.25 / 200g carbs.
Most people benefit from higher sodium content in their beverages, and there is little, if any benefit from higher potassium in endurance beverages. For all but the most extreme training and environments, with good hydration, table salt (sodium chloride) is sufficient to maximize performance.
In more extreme cases (hotter, more humid, very long-duration and high-effort) you may need to make a one-time purchase of sodium citrate (Amazon) to meet high sodium needs while allowing maximum hydration with reduced osmolarity.
Cost for table salt = less than $0.01 per 2000 mg sodium (sufficient for most folks 2-3-hr training, ~1 tsp)
Cost for sodium citrate = $0.10 per 2000mg sodium serving (~1.75 tsp).
Cheapest Gatorade Endurance Powder = $2.75 per 2000mg sodium.