Help! Need Pre-purchace inspector, Dallas Tx area/walk away?

Sayoung, that is an Internet Myth (actually the myth pre-dates the internet by several decades, but what the heck). There is no 3 day right of Rescission on vehicle sales in Texas, or most any other state. You buy it, you own it. Unless it has a specified, written warranty all vehicles come with an "Oklahoma Guarantee" which states: "if it breaks in half, you get both pieces".