2011 Toyota tundra purchase or Run?

Hi, everyone. I’m new here. seeking guidance and the honest truth.
should I buy or RUN?
it’s a 2011 Toyota Tundra limited Trd-off road and has towing package too.
It’s a 4x4, 4wd,
And it has 138k miles on it and only 2 owners.
The guy bought it in Maine at 60k miles and came down to Austin, Texas.
The Cons are Rust, rust, rust and heat shields are making noise.
He wanted 16.5k for it and we agreed on 15k flat.
Is this a good deal? Or should I run because of the Rust?
There’s one picture it shows too right that the rust is flaking? also there’s rust under the hood on bolts and screws.

 

That rust doesn’t look terrible for living in Maine. Is that the only pic of the underside?

I’d spend a day underneath with a wire wheel, then paint, then coat seasonally with a few cans of Amsoil heavy duty metal protector.

 

Looks decent to me. The rust is just surface rust as far as I can tell.

 

The rust doesn’t look that bad.the rust shown is surface rust. $15 isn’t bad considering today’s market.

 

That's not rust, lol. Rust is when there's no black left on the frame (or Toyota covered the frame in undercoating).