I'm cheap. I inspect the rotor and if they're not grooved or obviously damaged, I just replace the pads. You will, however not want to get too cheap on wear parts. Ceramics are worth the money in terms of reduced noise and dust plus better longevity. The common theme I'm seeing from other members is buy a name brand, not a store brand pad. As for whether to just replace fronts or do the back brakes too, the best answer to that question is to replace them. I've not had to replace the brakes on my F-150 yet, so I'm not all that familiar with how back pads will wear versus shoes, but as a rule, I'd replace two sets of pads per set of shoes in the back on my Ranger.
Been doin' it this way for thirty years!