Morton Lite Salt, Magnesium citrate liquid (or powder like Calm), and fruit like lemon/lime/berries or squeeze of water flavoring like mio.
That gives you sodium, potassium, and a form of magnesium your body can easily absorb for a fraction of the price of electrolyte packets.
1/4 tsp Morton Lite Salt
1 TBSP magnesium citrate liquid (or 1 scoop of Calm magnesium citrate powder)
18-24oz of water
Fruit or squeeze of water flavoring
You get 290mg sodium, 350mg potassium, 145g magnesim (162.5g if you use Calm magnesium citrate powder)
Note: be careful and don't add a bunch of the magnesium citrate. It will make you shit yourself if you get too much of it.