I can understand peoples fears. This is very new, but I believe it is the way of the future. In the past, people were afraid of mail-order, but look at it now. I have purchased many items on the internet and have not had any problems. The best suggestion I can give is to be sure you are on a secure server.
Many web sites offer secure servers to conduct credit card transactions.
If it does not, I would not do it. Also, only deal with a reputable company. I am personally weary of companies that offer a service. One of the most convenient items to order on the internet is audio CD's from CD-NOW . CD-NOW allows you to search for all kinds of music CD's or video tape.