I have heard this verse quoted many times to justify a wrong doctrine that Christians should possess nothing, but that misses the point of the story. The issue was not that the young man had wealth, but that the wealth had him. His trust was in his riches and his position and Jesus’ instruction would have meant a transfer of his faith onto God as his source and provider. The question Jesus was really asking him was; "will you put your trust in me?" We would undoubtedly describe the young man as materialistic.
The thing is, you don’t have to be rich to be materialistic, in fact some of the poorest people I have met have been the most materialistic of all. I have seen people who clearly have very little in terms of wealth queue up to buy a lottery ticket on a Friday afternoon, in the vain hope that a huge windfall would make them happy. I have seen people seemingly give up all common sense in order to participate in some get rich quick scheme to get hold of the possessions they so crave after. Even more sadly, I have seen ministers of the gospel compromise their integrity and fail to confront unrighteousness in their own church, out of fear of losing their job and security. The Bible tells us that it is faith that pleases God (Hebrews 11:1), and faith means that we trust Him as our source no matter what the prevailing circumstances might be.
Jesus told us that it is the pagans that worry about and chase after wealth. He instructs us to seek after His government in our lives and His righteousness, which is by faith, and all the things that the world worries about and seeks after, God would supply to us anyway. (Matthew 6:25-33)