Really depends on which country you are in, in my country you can buy via anonymous cash deposits over the counter in most banks, just use as fake email address to book the order and of course be mindful that your browser history could link you to the order but the chances of that happening are very slim. Remember bit coins are not illegal and can now be used to purchase all sorts of things, not just goodies on SR. There are some reputable vendors on SR who sell bit coins, just make sure you do plenty of research before taking the plunge to avoid getting scammed, as a general rule the posts that spam up the forums are scams (e.g. Virwex).