Opinions please...

Ebay or Craigslist, just make sure they look ok before buying

Better and cheaper don't go together. I would go with a ReadyLift leveling kit. Watch out for cheap leveling kits as many have torson keys made in China.

X2 on cheap torsion keys, Ready Lift keys are forged not cast. The torsion keys support the whole weight of the front of your truck, and cast keys have been known to break under the stress, it is rare but why take the risk and skimp on quality to save a few bucks. The kit you have the link to is essentially a lift kit since it also has a coil spacer for the rear. Are you wanting to lift the truck and put on larger tires or do you just want it to sit level? Rough country are notorious for lower quality, keys and spacers are probably O.K. but I wouldn't put too much faith in the shocks, I can't see them being real high quality for the price. If you just want to raise the front a little then I would look at Ready Lift or Pro-Comp.