Yes, your client will have to pay long distance to send the fax if it is not in their area. Most of my clients are all over the country, so they would have to send it long distance anyway.
I used efax for quite a while. Then I started getting too many faxes, and they sent me a message saying I'd have to upgrade or risk losing my number.
If you have to upgrade, I suggest using
MyFax because I think their paid plan is better and costs less than efax. (But efax certainly is the company of choice for a free plan as long as you don't receive too many faxes). MyFax's plans start at only $10 a month and include a generous amount of outgoing faxes as well.