As a marketer myself and someone who advises small business owners on this, you're far better off calling them than emailing them. First, with the right phone script, you'll get a much higher response rate. Second, you don't risk getting your email list account dropped because you bought a list and your subscribers didn't actually opt in to receive YOUR marketing messages.

This especially applies in any "non-techie" industry such as the one cited (hair dressers). Non-techies are far more likely to hit "Report Spam" than to find the unsubscribe link at the bottom of each message.