My favorite place to shop for supplies is Craft's 2000. There are only three nationwide, and fortunately one is nearby. I bought several paper mache jewelry boxes for $1.99 each (at Michael's Craft Store they are either $2.99 or $3.99) and plan to list some on eBay and give some as Christmas gifts.
I found a piece of ocean/map themed scrapbook paper laying around that I've been dying to use, so my first jewelry box was one in a nautical theme. Excluding drying time, this project takes about 45 minutes to complete.
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After the paint had plenty of time to dry, I added a thin coat of clear, matte varnish. I do this by using a stiff, flat paint/craft brush and apply the varnish to the brush, not the paper mache item. It's important with paper mache to keep coats of glue, paint and varnish very thin. If you apply too much (and "too much" can be very little) paper mache will bubble. Some prefer spray varnish. I've found that if I'm not careful in applying that, it too will bubble if I spray too long in one area. Liquid varnish works best for me.
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While the inside was drying I cut pieces of my scrapbook paper to fit the sides and top of my box. Again, I used an old paint brush to thinly spread the glue to the areas where I would apply paper. After you've given the glued paper sufficient time to dry (I would wait at least an hour) apply another very thin layer of varnish over the areas where you've used paper.
Now for the fun part, the embellishments! I used thin twine to around the top and bottom of the box to create the look of rope. Next, I applied tiny seashells and starfish to the top using E6000 glue. Inside, the same, but added a pygmy seahorse. Let the box dry overnight before handling.