Hi Paul,
There are too many variables, only one of which you've given, for a simple answer. For example:
.. does your system support faxing, or do you need to buy/install additional hardware/software?
.. does your ISP support faxing, or do you need to use a standard telephone connection?
If it's the latter:
.. what telcos operate in your area?
.. what are the telco charges?
.. are the faxes to local or out-of-area destinations?
and so on. No one here is likely to have the resources to work all this out for you and, since it's only for "a few faxes", the cost
of doing so is probably far more than any savings that might be achieved.