Hit me and do what though? That's the bit that loses me on these hypotheticals. I can't think of any time I've bought something that wasn't researched or didn't sit in a checkout basket for at least a week. And this is maybe only a few times a year, most months I don't buy anything except groceries. I don't trust AI but I'm unconvinced about how successful it could be at manipulation.
Advertising is likely far more successful at manipulating you than you realize. When it comes to purchases it will show you only a narrow subset of what's avilable to you. Amazon does this already when it shows you the same products over and over again then starts showing unrelated products or stops showing new results entirely.
Product advertising is bad enough, but it's not just about trying to get you to buy something. AI will also shape your opinions and your political views. It'll hide or downplay information to protect paid partners and advertisers. It'll lie to you in order to convince you that there are things you urgently need to do to protect what you already care about, when in reality doing those things will be ineffective or even counterproductive. It will show you things to keep you angry, or afraid, or feeling helpless. It will distract you from doing things that could bring meaningful change. It will influence how you vote.
Even if you are somehow more immune than most people to cognitive biases and the psychological manipulations employed by advertisers, marketers, and PR firms most people around you will not be.
When will it do this exactly? Will we be watching AI generated movies and listening to AI generated music that is altering our politics? I don't see the avenues you see for AI to lie to me, perhaps someone who uses social media, or reads news websites, or opens spam emails might find themselves vulnerable - but I think you can live a good life without ever exposing yourself to or caring about this kind of nonsense.
I should point out I don't use Amazon, nor would I use any retailers website to inform myself about available products when I need to buy something.
I suspect we increasingly will (and in some cases already are). As you say, anyone using social media will find bots shilling ideology of one kind or another and usually with ads on top of the astroturfing. It's only going to harder to sell who is a person or an AI pretending.
Anywhere you see an advertisement is an opportunity to manipulate you. Compared to most people I see very few ads myself, but I sure can't escape all of them. Limiting our exposure to ads is the best defense we have against them, but increasingly they part of the content we want. Ads are being inserted into more and more places in our lives. AI will be too.
When buying something, I wouldn't use some source or community that I'm not previously aware of. I understand that advertising must work, to be such a profitable industry, but I guess my brain just isn't wired that way. I find it very easy to never buy things that aren't necessities.