6 years and 60k isn't bad. The stock shocks are not the best anyhow, and you could be seeing some wear on them. What exactly is the "noise" you're hearing?
Are you seeing and hearing any other symptoms? Like additional vibrations through the truck after hitting bumps/bridge expansion cracks/railroad crossings.
For a 2wd application, check out Monroe, KYB, and Bilstein offerings. You should be able to get all 4 corners for about $350, or less if you can find them on sale. Bilstein will be a touch more expensive.