Mine webshop history for clusters
Frequent Item-Set Mining is what you are looking for. You can see the tree structure of your frequent itemsets and the association rules afterwards.

For your data I'd suggest to look at the whole for a while to get a sense on what you have in hand. Playing with concepts like Probability Distributions, Entropy, etc would be really helpful in case you can reduce the size of your features. 

PCA also gives you the opportunity of projecting your data into a low-dimenstional space and you can see also plots showing first several PCs in 2-D or 3-D and get an impression about your data.

Before all above I strongly suggest to see if you have Missing Values and if yes try to cope with them.