Basically, internet use is forbidden. However there are some exceptions. If internet use is needed to earn a living, and other options are not available, it is permitted to use the internet. It is also permitted for case of Jewish outreach, research and in certain cases for educational purposes. If already permitted for one of the above reasons, then it is also permitted to do "internet shopping" for oneself or others.
However in all these cases, a hareidi religious Jew cannot decide for himself that he qualifies, but must ask a ''shailat Rav'' and receive a letter in writing authorizing the use.