To do an electric fence, you need:
4. The power unit
5. A gate of some kind
6. A ground rod
For wire, there are three kinds, braided (or polywire), solid aluminum and solid (zinc plated) steel. I prefer aluminum, but they all work fine. I've never used the braided (fabric + fine stainless wires), so I have no idea how you join it or hook your fencer to it.
For posts, I prefer steel T posts, available at any big box handy/lumber store, couple bucks each. You can pound them in with a hammer if your ground isn't totally rocky. For wee little/short fences, they sell wee short little fiberglass poles that are pretty short. If there are ABSOLUTELY no branches that overhang the fence, these will work fine to keep coons out. They are very inexpensive and you can basically push it in the ground by hand.
Insulators, get ones to fit what ever posts you chose. They are cheaper by the big bag. Most big box stores carry the ones that fit a T post. If you already have wooden fence posts, there are special insulators for that too, then you don't even have to buy posts.
If you keep the weeds off your fence (they short it out, so the animal doesn't get much, if any, shock), you don't need a hundred dollar fencer. Here's one for $30 with free shipping:http://cgi.ebay.com/Zareba-A5-Electric-Fence-Control-5-mile-range-/180521105226?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item2a07e5774a
You need some kind of gate that you can open that the coons can't crawl over. You can use special gate hooks so you can open and close the electric fence itself, like here:http://cgi.ebay.com/Medium-Duty-Gate-Handle-Orange-Electric-Fence-/400080809197?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item5d26acaced
The ground rod is just a piece of steel rod, usually zinc plated so it won't immediately rust. Pound in the ground, hook to your grounding post of the power unit. Any old piece of galvanized pipe would work just as well if you are a scrounger.
If you do an ebay search for "electric fence" you can educate yourself on about everything you'd need in 20 minutes.
Good luck and keep us posted!