Here's what I need to do:

Invoice and average of 50 different customers each month for one or more of
the dozen services I offer.

I figure I need a database of contact info with each person being assigned a
unique i.d. number.

I also need a database of services

I need a form that pulls info from both databases and provides a total with
or without tax depending on the service.

So my question is, how do I go about doing this? Is excel even the right
program for me or do I need to incorporate access?

Cheers!