Considering a 2006 Tacoma....

I wouldn't get discouraged, just use due diligence and the info you've found to make an informed choice.
Remember opinions are just that "opinions", everybody has one.
On my 06 the rust wasn't that bad, I probably coulda drove for another 6 or 8 years before the frame became an issue, as it was toyota offered to put a new frame under my truck so I took it.

I have seen 1st gens here in the rust belt that still have good frames, so while it's an issue it's not the end of the world, you just have to be informed to make a choice.

 

Think about this, if they offered to buy it from him, it must have resale value, they wouldn't have bought it for scrap or to replace the frame before they could sell it.