Here's a quick and dirty build for organizing a messy drawer. The bottom is made from a 1/4" birch panel that I had left over from another project. The sides are made from 1/4" MDF.
I started by measuring the inside of the existing drawer. To make the base, I subtracted half an inch from those dimensions to account for the 1/4" sides, then I used a circular saw to cut a rectangle from the birch. Next, I cut (4) 2.5" strips of the MDF to make the sides. I just lined the strips up against the edge of the base and eyeballed the measurements for the width and depth, then I cut them to length with a portable jigsaw. Finally I used some glue and clamped everything together with a strap clamp and let it sit overnight.
Next, I cut out several 1.5" strips of MDF to start making the partitions. I took all the junk from the drawer and came up with a layout, then started cutting the strips to length. The most efficient approach was to glue in the longest strips first, then divide those spaces up with the smaller strips.
Once I had all the partitions done, I added some white matte cabinet liners that I sitting around. I hadn't planned on using the liners, but they did a nice job of covering up blemishes and glue spots in the wood, and they keep everything a lot cleaner inside.
Finally I had to completely pull out the drawer so that I could drop the tray into place. I purposely undershot the width and depth to make sure the tray would fit (it would suck to finish and find out it was a millimeter too wide), so I had to use some shims to make it fit snug in the drawer.
Finished product cost me about $10 worth of wood, much cheaper and must more customized than those one-size-fits-all bamboo deals you would get from the store. Not bad for a days work!