Zippo is great. Free repairs (not counting shipping), customization, and awesome legacy.

When it comes to customizing your lighter, however, Zippo is very restrictive: you may only fit a certain size parameter, you cannot engrave the sides, and uploading image designs cost a whopping $15.
Custom engraving companies are willing to engrave your Zippo lighter... for a $10 minimum and about $2 a word. Restrictions also apply.

Having more time than I have money, I decided to engrave my Zippo lighter by myself.

This is the first time I EVER engraved something, and I got pretty satisfying results: You can do this too!

EDIT:
Here's an instruction video I made for a different lighter for a friend; essentially the same steps I took to make this Zippo lighter, except with more shortcuts (for lazy people):

Step 1: Materials

Most of these instructions were inspired by this Instructable by Kactapuss. Maybe take a look at that before proceeding.

Materials

Scrap Metal
Dremel + diamond engraving bit
Plain Zippo lighter
Permanent marker
Masking tape (a light color)
some sort of smooth tape (packing tape)
Hobby knife

Step 2: Generating Ideas

I can't really help you get an idea.
I have two pictures of what I wanted my lighter to look like when it was finished.

...

But once you have that idea you need to format it to fit your lighter. You may need to play around with the font size and print out multiple copies of your design to match sizes with your lighter.

Attached is a copy of the final font an size I used for my lighter. (If you don't have the font download Bebas Neue).

This step is a lot of guesswork and no real measurement. The only measurement used in this step was the ruler in Microsoft word, and the dimensions of the lighter (1.5 x 0.5 x 2.25).

Keep printing until you have the right size. I recommend you use scrap paper ;)

EDIT:

I heard that Photoshop had this measurement feature, so if you know what to do and you prefer doing that, go ahead! I still recommend you to match up before you finalize the stencil.

bagbang.docx
Download

Step 3: Printing

After you have your final formatting finished, go ahead and put some smooth tape over where the right fit is.

After that, put the masking tape on top of the smooth tape. The glossy finish of the smooth tape is there to assist the removal of the masking tape.

When you have finished taping, print your final design again. Make sure to print Best Quality, because the ink might smudge off.
I used an inkjet printer and that was a problem; maybe laser jet printers have less of this issue?

Step 4: Practice

This was my first time engraving so I had to practice on something before breaking a bit, or ruining my lighter, or something else.

Take the masking tape off of the paper and lay it on some scrap metal.
Use the Hobby Knife to carefully cut out the design.
After cutting out the design, use the permanent marker to shade in the exposed metal.
Engrave the bare metal.
Take off the tape, and examine.

The instructions above were brief, and I will go into them further. The whole point of this step is to gain the feel of your Dremel, make mistakes, and get a little bit of experience before diving in.

Some things I realized while practicing:

Engrave edges before filling in
Do not rely on the tape to keep you in line
Engraving is just like using a crayon.

Step 5: For Real This Time

After practicing you should know how to proceed this time.

Prepare your printing surface again: Lay down some gloss tape and put the masking tape on top. Make sure the tape is flat so your printer doesn't jam.
I printed the design in Best quality with only black ink.

Take out the Zippo insert from the lighter to keep it clean and tape the case shut to keep it from opening.

Take the tape with the design and lay it on the Zippo where you want it to be. When pressing it down, I used the tape roll to roll over it, then I pushed it down with my thumb. You want the tape to be secure so it's easier to cut.

Step 6: Cutting for Real

This time you can't make mistakes.

Cut out the letters like you did on the scrap metal, but this time even more carefully.

Tips:

Cut away towards corners, not away from them
Don't cut through two layers of tape like I did. remove extra tape before laying on the second one.
Turn your lighter when cutting curves, not your hand.
Make several passes to make sure all corners are free and the tape is completely severed.
When peeling off letters, use your knife to hold down the empty spaces

After cutting and peeling, shade in the design.

This step is pretty time consuming so be patient.

Step 7: Engraving for Real

Having the right tools and methods is essential to getting the right results.

The following are some tips when it comes to engraving.

Apply light pressure, but make sure you apply enough pressure to engrave deep enough.
Keep the design an even depth unless you want varying depth.
Hold the Dremel like a pen.
Hang the Dremel from a stand to assist you in holding your Dremel. I hung it from the desk hutch
Clamp the Zippo lighter gently
Shut of the Dremel after each letter to give yourself a break, give the Dremel a break, and to examine the letter before moving onto the next one.
Be patient and be careful!

For this design I wanted to have the brass lettering show up, so I engraved pretty deeply. It will be more difficult to keep the chrome plating underneath. You probably can only do that with laser engraving.

If you have any questions they are all welcome!

Step 8: Cleaning and Finish!

After you are finished, take off all the tape and check for any mistakes or incomplete parts.

After completing, clean off the case with some nail-polish remover.
Replace the insert and admire your self engraved lighter!

I knew this would happen but I never mentioned it: The brass will oxidize hours after you engrave it. If you care about your brass staying shiny, maybe find some sort of lacquer to coat the brass part of the lighter. I did not coat mine because I didn't care about the shine, and I wanted a pure metal surface.

I want to give a special thanks to the eBay seller who sold this lighter to me for $7, my friend, and my sister for encouraging this experiment.

I hope this helped you and if you have any questions, please ask!
Thanks.

BangBang.