There is expensive because of brand and expensive because of material quality, do your research.
If "do your research" means take a couple minutes to make sure there aren't glaring red flags about a purchase, then yeah that checks, but I see this phrase used as a more serious concept which just doesn't seem realistic given my experiences.
I feel like if you don't already know what to look for in your specific product of interest it's impossible to do research and have confidence. Like when I don't know where to start and try to research products through a search, I go through so much SEO bullshit in such a short timeframe that I have no confidence in anything I'm looking at, including the stuff that looks like it has a good chance of being legit. Maybe I can find a forum of some sort, but I'll need a way to tell that the users aren't just talking out of their asses (or bots, or paid sponsors). Major review sites are a mess.
The phrase "do your research" is way overstated, because someone who knows what they need to look at is already going to do research and is not the target audience. The time it takes to filter through all the nonsense and form a coherent opinion researching something from scratch is so enormous that it's hard for me to imagine someone actually doing that diligently for anything less expensive than a car. What actually happens is you just give up partway and make your best guess like you would have done in the first place. At that point your research has led you to seeing a bunch of ads and a few conflicting opinions. Yeah, that will influence your decision and possibly be helpful, but the benefits are marginal compared to the time investment, it's rarely worth more than a few minutes if it's not a major purchase.
Or maybe everyone else is a lot better at this than me and I'm making a fool out of myself by posting this.
The fact that you understand that something is an ad is a undervalued skill, sure there is lots garbage to go through(it's the current state of the internet), but it's not like you are looking at 12 brands of pasta at supermarket, just picking one it's ok in some scenarios.