If you are in that group of business owners, did you ever consider what the receiver of that type of email thinks about your business or your professional image when they realize that. Free email accounts are great, nothing wrong with them if you are using them for sending email to family and friends, but they are bad for your professional image.
Register domain name for your business end send all your business emails professionally from your domain name (for example, anyname@yourcompanyname.com). In this way your email is always consistent and at the same time you advertise your online business.
EMAIL TIP: Always respond to your email inquiries professionally and on time.