Carmax has several in the area, including a couple of 2014 Lariat, Crew Cabs with under 40K, for under $30K.
Texas Autodirect has 2015 Lariat with the Ecoboost engine (better mileage) $29K
2016 - Aluminum and Ecoboost engine = 25 mpg
https://www.texasdirectauto.com/for-sale/Ford-F-150/vehicle/1FTEX1CP8GKF45247