I wouldn't say that this would be known as materialism as it has a meaning for what's worth of it. Materialism is a tendency to consider material possessions and physical comfort as more important than spiritual values, but in this case, the fact is that buying these materials are a part of the process of spirituality, I would not consider buying things such as butter lamps or silver offering bowls...materialistic.
Some would say, one's alter can tell quite a lot about that particular person/group; the way it's positioned, his/her/their sense of style etc. Ones alter represents to his/her/their personality. Expensive offering items and statues are brought not because we want to show off but it's because it represents a release of attachment of money by offering the best and most affordable quality to buddha. When you bargain it shows how much attachment you still have and that your not even willing to sacrifice your money for your spiritualism.
When your having an alter, there are some important steps you may need to follow. Which includes:
1)image of your lama
2)image of lama tsongkhapa
3)image of dorje shugden ( the best is to hv a statue )
4)dharma text on the left (can be any dharma books like Lamrim)
5) a stupa on the right
if your altar is big enough , try to offer as many sets of water offering as you can and also if you afford to offer eight auspicious signs.