My company used to only sell their education products (some priced over $100) by taking faxed in orders or by phone. Orders range from $20 to $800.
I instituted a Shopping Cart system to their website, SEO'd the product page and other pages to get them better rankings for the products. Sales are a little better in that we saw about a %30 increase in sales of product over the phone in method. We now offer all three methods. The only time somebody phones in an order is when they kind of goof up with their cart. That has happened 2 times in the 1.5 years the cart has been in operation.
We clearly show our addresses, phone numbers, email address (hidden from harvesters by javascript) and our smiling faces on the web site. I think that is important for converting visitors into buyers.
I use authorize.net for my payment gateway and
http://www.king-cart.com/ for my shopping cart. I love the way
http://www.king-cart.com/ allows me to create the code using their tools, then lets me post the actual code directly on my web pages on my server. I have had zero fraudulent charges or attempts to exploit my product page.