I spent about $10 for all the supplies at Radio Shack, not including tools.
You will need the following:
Solder
Soldering iron
Small gauge wire(I used 20 Gauge)
6 5mm red LEDs
1 10 mm high brite LED
D cell battery holder
Electrical tape
Switch (optional)
Cardboard out of aspirin or vitamin bottle cap
LEDs do have a positive and negative terminal. The short terminal is the negative. I marked it with a Sharpie to make things easier.
Push the pins of the 10mm LED through the center of the cardboard circle from the aspirin bottle.
Push the other six 5mm LEDs evenly around the center LED.
On the backside of the cardboard, separate the positive and negative terminals. I angled all of negative terminals towards the center into a "bird cage" shape. I bent the center positive terminal over so it laid between two of the other LEDs' terminals. I bent all of the positive terminals to the side so they overlapped each other. If you need to "bridge" any together you can use wire or extra LED terminals like I did. The picture isn't great, but hopefully it clears up my less than stellar explanation.
I soldered all the terminals where they overlapped each other to keep them well connected. Don't get to picky, a glob of solder over each section is fine.
Solder the leads onto the positive and negative terminals. Black is always negative, and red is always positive.
Attach the battery pack leads to the appropriate leads from the "eye."
If you want a switch, simply solder it in line by cutting the positive wire, stripping the wire ends, and soldering the switch in.
Use electrical tape and cover all of you solder joints, and you're done.
And here it is lit up.
I made it for my Spider/Skeleton (hence the multiple "eyes"), but the same process would work with just one LED.