Displaying a Toll Free Number is a quick, easy, and surprisingly CHEAP way to add credibility and professionalism to your online store.  I pay only 2$ a month for a toll free 888 number, which is forwarded to my home line.

Kall8.com has a great referral program

I pay an additional 2$ a month so that these calls are "announced".  This means a quick recording is played after someone answers my home phone, indicating the call was made to the toll free number.    And THAT means I know to answer (again) in my "business voice"... and that my husband and kids know to HANG UP!  (During the time of the announcement, the caller hears the line as though it has not been picked up yet, and then hears the voice mail greeting when we hang up on our end.)

The basic 2$ a month includes voice mail, with the messages immediately emailed to me as audio files.(You could choose to call in to listen to your voice mail -- great for on the go business owners). And, an email after every call made (hang ups, completed calls, and voice mails) with all the caller ID info available, typically including the phone number, first and last name of record, and city/state.

I use Kall8.com.   And have been VERY happy with them. 

You my have a smart phone --- but don't forget to use a smart phone number too.
Happy calls!