Patricia,
I use Updox here at our office. We are saving on ink toner & paper for the fax machine. I like it as it integrates with AC but does cost $35/month for 3 users. Updox price would also depend on the number of faxes/month. The basic rate comes with 500 pages/month. If you used Updox, you could get rid of your fax line and that would save you some money as well.
Certainly a MFC would work too. You'd have the initial investment of the machine (if you don't already have one), but you wouldn't have the monthly expense like in Updox.
I wish all our specialists would fax us letters after seeing our patients. I'm lucky to get 10% of any consults.
