You're lucky: ball joints on these are a bolt-on, not a press-in. I've used the small tie rod end puller (looks like a gear puller) to pull both on my truck; I had borrowed Autozone loaner tool a few times over the years, then just bought it. I've seen similar at Harbor Freight.
http://www.harborfreight.com/tie-rod-and-pitman-arm-puller-62708.html
Advice: do both ball joints on a side at one time, easier access; use a jack to support the rotor as necessary, and of course jack stands for the truck. Some replacement lower ball joints may have grease fitting, you may need to notch to get fit for that. Also, after loosening the ball joint or tie rod end nut, keep the nut on loosely so puller end doesn't slip off. Measure tie rod effective lengths so you can get close enough to drive to alignment shop. You may need an impact wrench to get the new nuts to tighten and not just spin, or use a LARGE ViseGrip or Channelock to compress such while you start to tighten the nut.