Personally I think the bar will be very high. If you have a bot that is explicitly there to sell you something, you can probably demand that any sale it makes

Personally I think the bar will be very high. If you have a bot that is explicitly there to sell you something, you can probably demand that any sale it makes of that thing is legally binding even if you're obviously gaming it because the bot does have authority to negotiate a deal. It's not supposed to sell it for 90% off. But you'd have a very tough time arguing it lacks the apparent authority to do so. The 10k example is erroneous by other basic case law. There's no consideration on your end, so it's not a binding agreement. Nor does that sales rep bot likely have authority to be purchasing things from you (of course, that could change based on context).