Here is how I made an easy cheap 90g glucose:fructose mix from two easily obtainable premade items. You can probably get them for a bit cheaper or comparable items. I get the gatorade powder from my local grocery store for ~$5/container but the pricing is similar from amazon
This basically a mixture of table sugar(50:50 glucose:fructose), dextrose(glucose), electrolytes, and flavoring.
I assume for simplicity that its essentially 50:50 glucose:fructose by weight since I don’t know the exact composition so for 90g, i’ll need 30g of fructose or 60g of gatorade mix, which is about 3x the recommended dosage from gatorade. 23g/12 fl oz(350ml) or ~60g/22floz(650ml normal bottle size)
To make up the remaining glucose, you could buy glucose powder or maltodextrin powder. I chose maltodextrin powder as I know it will not be sweet and it will keep the overall osmolality of the solution down. I use this one because its pretty cheap/g and its in a nice container for storage and of known origin and dissolves relatively well. Its corn based and some prefer rice based tapioca maltodextrin or even cheaper from a local brewery supply store in bulk or a health food store
I used a scale I tared and an old SIS container to mix in at a 2:1 ratio, 200g gatorade:100g maltodextrin
Did some back of the napkin math to calculate grams of carbs and mg of electrolytes
Since I didn’t know the ratio of sodium chloride(NaCl) to sodium citrate(C6H5O7Na3) or potassium phosphate, I couldn’t determine the chloride and citrate ion concentrations to compare to SIS but its in the right ballpark
So for ~$25 you can make ~25 bottles of 90g fake maurten/betafuel or ~$1/bottle with lots of maltodextrin remaining, or for ~$40 50 bottles, or $0.80/bottle, or 1/4-1/3 the cost of beta fuel.
In terms of flavor/sweetness I find it pretty palatable mixed at this concentration and comparable to the SIS GO powder due to its use of artificial sweeteners, and its easy enough to dissolve in a bottle with vigorous shaking. Bonus, you can also just mix 60g of maltodextrin in a bottle for an almost flavorless carb bottle for training when you don’t need the electrolytes or going on a short ride for ~$0.10/bottle.