after 8 months of driving I find that I must have messed up something in the frontend. I just noticed that the inner thread of both front tires are worn off and the steel wire is exposed. WTH! What does that mean? Toe in/Toe out?, camber, as the garage guy told me?
Toe-out, and/or negative camber (most likely it's toed way out if it only took 8 months to happen).
Since you're inclined to DIY, have you looked at this article?
www.therangerstation.com
From what you described happening to your tires, it sounds like potentially the suspension was bound up slightly when you adjusted it 8 months ago... This shows (about halfway down) how to relieve any bind or tension between the two front tires so your measurements will be accurate (the binding can come from a number of reasons, one of them being bad toe, another simply from how the truck was parked). It's written for a 4WD, so the part about beam pivot height likely won't be the same if you have a 2WD, but everything else is essentially the same procedure.
×2 on the garbage auto parts... there's a ton of shit out there now. Given the current dismal state of the ball joint market, I wouldn't trust anything not having the Motorcraft name (hopefully they're still available).