Charging too much can do several things. It can point the customer away. It can make you lose business, and can decrease the amount of sales you get. If your prices are above average, then you need to make sure you express your strengths in customer support and quality of your product or service. Your site is like your storefront.
First appearance can mean getting the sale or loosing it.
You want your site to be professional, clean, and easy to navigate. People will feel more comfortable about buying something from you, if you give off a professional image. When potential clients contact you, try to respond to them as fast as possible. Also make sure you answer their questions fully, and professionally. You want to sound like an executive officer.