New to Apache, Q for an application

I hope it's OK to post this here. Originally I was planning to create my
first web server using IIS and .NET because a relative had easy access to
all the right technologies and equipment. However, I don't feel comfortable
with spending that much money on software for this small company project
even though it could expand in the future. So I've switched to using
Apache.

I would like to run a business website for wholesale ordering by customers.
The server would be at a seperate location but must be accessed by offsite
ordering personnel to package and ship the goods as well as billing using,
preferably, an application of some sort.

I had just got into asp.net programming when I decided to switch so I'm
fairly new to all this but have a general grasp of how things work.
However, I would like to hear any suggestions as to how to bring all this
about considering I would have thought it would be relatively easy to do
using the .net paradigm. What would be the best way to communicate with the
server and the offsite application?

I'm not asking for a how to as much as any roadmaps you guys might have for
me. Thanks.