In my case, my wife did it. The ingredients were Dreamweaver and a lot of swearing at how useless Dreamweaver was but that it was at least better than <insert alternative software name here>. She spent a lot of time on it. Her background is design; this may have been a hindrance, as she wanted everything to look perfect.
You need to make the decision as to the value of your time. If you're happy to spend a lot of time on the job, do so. If not, find someone local who can do it for you. They'll do it so much quicker than you can. Ge someone local and you'll be able to sit down with them and wave your arms around if things go wrong. Get someone online and they may not care about you.
If you do insist on doing it yourself, then investigate Joomla; it's VERY quick to create content and had a million add-ons for things like online billing, etc. Google "Joomla" and you'll be inundated with useful material.
It's odd, isn't it? We would never think of making our own hosereel, pumps or brushes (some nutters notwithstanding), but for some reason when it comes to a website, we don't want to pay out for it.
Vin