I try to save money by buying generics when grocery shopping. But, sometimes it's not worth it. Years ago, my mom tried every kind of chocolate chip. She tried generic ones from various stores plus brand names. The only store brand chocolate chips that she liked were the ones from Trader Joe's. I've stuck with Nestle's or Costco's store brand ever since.
Cocoa is another one of those ingredients. Last year, I finally found a fudge recipe that was easy to make. First, I made it with Hershey's cocoa. Then, I made it with some store brand cocoa from Aldi. It wasn't the same at all! I'm going to stick with Hershey's from now on. It's too expensive to waste a batch of fudge on bad cocoa.
Vanilla is the last one that comes to my mind. Imitation vanilla or the real thing? Imitation vanilla has a strong alcohol flavor, but the real thing doesn't. I've stuck with the store brand vanilla from Costco or BJ's, for the seven years. Costco has the best price. A lot of people just leave it out of their cookies because it is an expensive ingredient. When my mom moved here last year, she had been leaving it out for several years. But, since I keep it in my home, she started using it again. And I think she's glad she did.
Flour, Sugars (brown, granulated, and powdered), salt, pepper, most spices, baking soda, baking powder, cornstarch... I've never had any issues when it comes to generics with these ingredients, though. So, I don't spend any extra money on them. Store brands work great.
I think that's the hard part about buying generics. They're a great way to save money on groceries. But, sometimes they can really affect the taste of what you're making!