A simple box made of inexpensive wood shims.
This project can be done over an extended period of time since it takes time for the glue to dry and set.

Step 1: Parts

1. 4 packs of wood shims (more if you want it the box higher). Home Depot usually has them for about $2 a pack:
http://www.homedepot.com/p/8-in-Homeowner-Pine-Shims-12-Per-Bundle-PSH8-12-12/100082960
2. Spring clamp and/or C-clamp (Home Depot has 2 inch ones for $1):
http://www.homedepot.com/p/HDX-2-in-Spring-Clamp-80002/100027346
3. Craft sticks or coffee stirrers (stirrers can come from a corporate cafeteria)
4. Glue, preferably wood glue, but this is workable with Elmer's School Glue as well. (Home Depot as wood glue for about $4):
http://www.homedepot.com/p/Titebond-8-oz-Original-Wood-Glue-5063/202180088
5. Paint, not shown. I usually buy the small containers of mistake custom colors from the Paint Dept at Home Depot for a good price. Or you can buy tempera paint that artists use:
https://www.pearlpaint.com/shop-Pearl-Tempera--8oz-Bottles_80000_80062.html

Step 2: Build Base

1. Take 2 wood shims
2. Take 2 clamps
3. Glue the 2 wood shims together
4. Since wood shims are generally low quality wood, they will be warped, so they will not fit together cleanly. Use the clamps to force them together. Fill in gaps with glue.
5. Use 12 shims to make 6 foundational base pieces

Step 3: Attach Base Pieces

1. Using the craft sticks (I used wood coffee stirrers), glue the 6 base pieces together.
2. Use glue to fill in the spaces.

Step 4: Glue First Crosspiece

1. Take a single shim, and glue it across the craft sticks that are holding the base together.
2. Use the clamps to make sure it is flat and flush. When you clamp it, glue the thick part down first, let it dry and then clamp the thin side with glue.
3. Fill in the gaps with glue.

Step 5: Glue 2nd Crosspiece

1. Glue 2nd crosspiece across from the first one.
2. Make sure that the thin parts of the shim are opposite the thick parts (see notes on picture).

Step 6: Repeat Pattern

1. Repeat the pattern of gluing additional shims, making sure that the thin parts are glued to the thick part of the shim below it and the thick part of the shim is glued to the thick part below it.

Step 7: Warped Shims

1. In a number of cases, the shims will be warped. (Shims are generally lower quality wood.) There are 2 ways to deal with this.
2. 1st way: glue the thick part of the shim down first. Make sure the warped portion is on the inside of the box.
3. Once it is dry, push down the corner of the warped shim until it breaks or gets a crack.
4. Glue the piece down and to the rest of the shim.
5. 2nd way: glue the thick part of the shim down first. Make sure the warped portion is on the inside of the box.
6. On the thin side of the shim, push the warped portion down and secure it with a spring clamp.
7. Glue in and around the shim to secure it to the shim below it.
8. Once the glue has dried, remove the clamp and add additional glue where it was clamped.

Step 8: Paint Box

1. When you reach the desired height, paint the box.
2. There will likely be dried glue visible on the sides and top, so a nice cover of paint will make it look clean.
3. Don't forget to do the inside portion as well.