Yeah I see where you're coming from. The only problem with bulk powders is that they can get pricey.
Depending on what you're looking for, I would at least take a look at Slinmax. It's a fully disclosed ingredient profile that doesn't contain anything unnecessary or any extra fillers like some GDA products do. It provides you with Na-R-Ala, agmatine, berberine, banaba, and trigonella - all of which have been studied to help manage blood sugar and help drive nutrients into the muscle.
I agree that most GDA products aren't worth the money between unneeded ingredients and prop blends, but a product like Slinmax might be worth your attention