For indoor training, I make my own. This is largely due to cost. If the ride isn’t that hard (below sweet spot), I just do electrolytes. This mix ends up being about 5 cents a bottle.
For more intense workouts, I’ll add varying amounts of maltodextrin to this. I haven’t done the math on the cost for that, but it’s cheap.
If you use commercial products at retail prices, you can easily spend several dollars/workout just in nutrition - you are paying a huge premium for some flavored sugar water with some salt in it.
For riding outdoors, I usually take a commercial mix with me, as that’s simpler. I usually take some Nuun tablets, as they are quite compact, and then some other mix with sugar. Nuun has some nice single serving packs for that too. I don’t usually go for the very concentrated stuff - usually Nuun/Skratch/Cranked or similar, and then some food and gels.
Here’s a post desrcribing my mix:
I’m still working through the large batch I made up at that time. Having used it for a while, and learned a it more about it I will try using sodium citrate in my next batch. It adds a bit to the cost, but is supposed to help with flavor a fair bit. Between the sodium bicarbonate and table salt it makes the water a bit bitter, so you need more flavoring to overcome that. Also I’d likely just stick with Sodium/Potassium if I was starting over, as I the rest isn’t really worth it. I have the calcium carbonate and epsom salt now, so I’ll use them in the next batch, but I wouldn’t buy them if I didn’t have them.