If you do not want to pay the upgrade fee to acquire a full MacDust license, you DO NOT HAVE TO.
Just (re)download 3.04 from your loot!
@izcale - xMod is not like MacDust, trust me - I worked with the developer on the Tools section of MacDust 3.
@MacGizmo - You will not find anything similar to MacDust on MacUpdate for the same price range, guaranteed. MacCleanse is more expensive, and nothing else really performs cleaning the way MacDust and MacCleanse do.
@bricklayer - You are more than welcome to continue using 3.04; just redownload it from your loot. This is not like SpeedDownload, you did not (and are not required to) pay for the MacDust loot.