Price is definitely a factor but I wouldn't let it be the only one. I do always give weight to a seller who is willing to reveal everything very clearly, and undercarriage pictures like that are a good sign.
However, after owning a vehicle that spent 8 years up north east before making its way to TX, I avoid them where possible. Mine looked pristine, with similar "surface" rust on some bolts. But try to take something apart, fuggitaboutit. You only hoped it broke in such a way that it fell off and you didn't have to drill/tap. After doing all of the suspension, armor, etc it was fine, but I had touched almost every bolt at that point. It was a royal PITA and after I sold it I told myself I would not do that again.
If you are from areas where all the vehicles around are like that and you are used to it, maybe it is fine. But in TX, I wasn't used to it at all and it royally sucked. You are fortunate to live in the western US where vehicles are usually pretty clean. I would keep looking.